EUROCODES. Background and Applications. EN 1991 Eurocode 1: Actions on structures. Dissemination of information for training workshop

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1 Dissemination of information for training workshop February 2008 Brussels EN 1991 Eurocode 1: Actions on structures Organised by European Commission: DG Enterprise and Industry, Joint Research Centre with the support of CEN/TC250, CEN Management Centre and Member States

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3 Tuesday, February 19 Palais des Académies EN Eurocode 1: Actions on structures Baron Lacquet room 9:00-9:10 Introduction by chairman H. Gulvanessian CEN/TC250 9:10-9:45 Introduction to EN 1991 N. Malakatas Ministry of Environment, Physical Planning & Public Works of Greece 9:45-10:30 EN N. Malakatas Ministry of Environment, Physical Planning & Public Works of Greece 10:30-11:00 Coffee 11:00-11:45 EN P. Formichi University of Pisa 11:45-12:45 EN S. O. Hansen Svend Ole Hansen ApS 12:45-14:00 Lunch 14:00-14:35 EN M. Holicky Czech Technical University in Prague 14:35-15:10 EN P. Formichi University of Pisa 15:10-15:40 Coffee 15:40-16:30 EN A. Vrouwenvelder TNO 16:30-17:30 EN J.-A. Calgaro CGPC, CEN/TC250 Chairman 17:30-18:00 Discussion and close M. Tschumi SBB-CFF-FFS All workshop material will be available at

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5 INTRODUCTION TO EN 1991 N. Malakatas Ministry of Environment, Physical Planning & Public Works of Greece

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7 LINKS BETWEEN THE Introduction to EN 1991 (Eurocode 1: Actions on structures) EN 1990 EN 1991 Structural safety, serviceability and durability Actions on structures Dr-Ing. Nikolaos E. Malakatas Head of Department - Ministry of Environment, Planning and Public Works - GREECE Chairman of CEN/TC250/SC1 EN 1992 EN 1993 EN 1994 EN 1995 EN 1996 EN 1999 EN 1997 EN 1998 Design and detailing Geotechnical and Seismic design Past and future of the EN 1991 (and the other Eurocodes) Parts and implementation of EN 1991 Time Period 1980 s Phase Technical preparation under EC Steering Committee CEN/TC250 Chairman CEN/TC250/SC1 Chairman Part of Eurocode 1 : Actions on structures Title (Subject) Issued EN General actions Densities, selfweight, April 2002 imposed loads for buildings EN General actions Actions on structures November 2002 exposed to fire EN General actions Snow loads July /2000 ENV (under CEN) Dr Breitschaft (until 1993) Dr Lazenby Dr Menzies EN General actions Wind actions April 2005 EN General actions Thermal actions November / ? EN (under CEN) Implementation Maintenance Harmonization Dissemination Further development Prof. Bossenmeyer Prof. Calgaro Prof. Gulvanessian Dr Malakatas EN General actions Actions during June 2005 execution EN General actions Accidental actions July 2006 EN Traffic loads on bridges September 2003 EN Actions induced by cranes and July 2006 machinery EN Silos and tanks May 2006 Partitioning of the NDPs among the Eurocodes Types of NDPs in the Eurocodes Type 1: Value (s) of (a) parameter (s). Type 2: Reference to some set of values table (s). Type 3: Acceptance of the recommended procedure, choice of calculation approach, when alternatives are given, or introduction of a new procedure. Type 4: Country specific data (geographical, climatic, etc.). Type 5: Optional National chart (s) or table (s) of a parameter. Type 6: Diagram (s). Type 7: References to non-contradictory complementary information to assist the user to apply the Eurocodes. Type 8: Decisions on the application of informative annexes. Type 9: Provision of further, more detailed information. Type 10: Reference to information Type 1 Type 2 Type 3 Type 4 Type 5 Type 6 Type 7 Type 8 Type 9 Type 10 1

8 EN : Densities, self-weight, imposed loads for buildings Forward Section 1 General Section 2 Classification of actions Section 3 Design situations Section 4 Densities of construction and stored materials Section 5 Self-weight of construction works Section 6 Imposed loads on buildings Annex A (informative) Tables for nominal density of construction materials, and nominal density and angles of repose for stored materials. Annex B (informative) Vehicle barriers and parapets for car parks EN : Actions on structures exposed to fire Forward Section 1 General Section 2 Structural Fire design procedure Section 3 Thermal actions for temperature analysis Section 4 Mechanical actions for temperature analysis Annex A (informative) Parametric temperature-time curves Annex B (informative) Thermal actions for external members Simplified calculation method Annex C (informative) Localised fires Annex D (informative) Advanced fire models Annex E (informative) Fire load densities Annex F (informative) Equivalent time of fire exposure Annex G (informative) Configuration factor EN : Actions on structures exposed to fire ( cont.) EN : Snow loads Forward Section 1 General Section 2 Classification of actions Section 3 Design situations Section 4 Snow load on the ground Section 5 Snow load on roofs Section 6 Local effects EN : Snow loads (cont.) EN : Snow loads (cont.) Annex A (normative) Design situations and load arrangements to be used for different locations Annex B (normative) Snow load shape coefficients for exceptional snow drifts Annex C (informative) European Ground Snow Load Maps Annex D (informative) Adjustment of the ground snow load according to the return period Annex E (informative) Bulk weight density of snow 2

9 EN : Wind actions EN : Wind actions (cont.) Forward Section 1 General Section 2 Design situations Section 3 Modelling of wind actions Section 4 Wind velocity and velocity pressure Section 5 Wind actions Section 6 Structural factor c s c d Section 7 Pressure and force coefficients Section 8 Wind actions on bridges EN : Wind actions (cont.) EN : Wind actions (cont.) Annex A (informative) Terrain effects Annex B (informative) Procedure 1 for determining the structural factor c s c d Annex C (informative) Procedure 2 for determining the structural factor c s c d Annex D (informative) c s c d values for different types of structures Annex E (informative) Vortex shedding and aeroelastic instabilities Annex F (informative) Dynamic characteristics of structures EN : Thermal actions EN : Thermal actions (cont.) Forward Section 1 General Section 2 Classification of actions Section 3 Design situations Section 4 Representation of actions Section 5 Temperature changes in buildings Section 6 Temperature changes in bridges Section 7 Temperature changes in industrial chimneys, pipelines, silos, tanks and cooling towers Annex A (normative) Isotherms of national minimum and maximum shade air temperatures. Annex B (normative) Temperature differences for various surfacing depths Annex C (informative) Coefficients of linear expansion Annex D (informative) Temperature profiles in buildings and other construction works 3

10 Forward EN : Actions during execution Section 1 General Section 2 Classification of actions Section 3 Design situations and limit states Section 4 Representation of actions Annex A1 (normative) Supplementary rules for buildings Annex A2 (normative) Supplementary rules for bridges Annex B (informative) Actions on structures during alteration, reconstruction or demolition EN : Accidental actions Forward Section 1 General Section 2 Classification of actions Section 3 Design situations Section 4 Impact Section 5 Internal explosions Annex A (informative) Design for consequences of localised failure in buildings from an unspecified cause Annex B (informative) Information on risk assessment Annex C (informative) Dynamic design for impact Annex D (informative) Internal explosions - D.1 : Dust explosions in rooms, vessels and bunkers - D.2 : Natural gas explosions - D.3 : Explosions in road and rail tunnels EN : Accidental actions EN : Accidental actions EN : Traffic loads on bridges Forward Section 1 General Section 2 Classification of actions Section 3 Design situations Section 4 Road traffic actions and other actions specifically for road bridges Section 5 Actions on footways, cycle tracks and footbridges Section 6 Traffic actions and other actions specifically for railway bridges EN : Traffic loads on bridges (cont.) Annex A (informative) Models of special vehicles for road bridges Annex B (informative) Fatigue life assessment for road bridges assessment method based on recorded traffic Annex C (normative) Dynamic factors 1 + φ for real trains Annex D (normative) Basis for the fatigue assessment of railway structures Annex E (informative) Limits of validity of load model HSLM and the selection of the critical universal train from HSLM-A Annex F (informative) Criteria to be satisfied if a dynamic analysis is not required Annex G (informative) Method for determining the combined response of a structure and track to variable actions Annex F (informative) Load models for rail traffic loads in transient design situations 4

11 EN : Traffic loads on bridges (cont.) EN : Traffic loads on bridges (cont.) EN : Traffic loads on bridges (cont.) EN : Traffic loads on bridges (cont.) EN : Actions induced by cranes and machinery EN : Silos and tanks Forward Section 1 General Section 2 Actions induced by hoists and cranes on runway beams Section 3 Actions induced by machinery Annex A (normative) Basis of design - Supplementary clauses to EN 1990 for runway beams loaded by cranes Annex B (informative) Guidance for crane classification for fatigue Forward Section 1 General Section 2 Representation an classification of actions Section 3 Design situations Section 4 Properties of particulate solids Section 5 Loads on the vertical walls of silos Section 6 Loads on silo hoppers and silo bottoms Section 7 Loads on tanks from liquids 5

12 EN : Silos and tanks (cont.) EN : Silos and tanks (cont.) Annex A (normative) Basis of design Supplementary paragraphs to EN 1990 for silos and tanks Annex B (normative) Partial factors and combinations of actions on tanks Annex C (informative) Measurements of properties of solids for silo load evaluation Annex D (informative) Evaluation of properties of solids for silo load evaluation Annex E (informative) Values of the properties of particulate solids Annex F (informative) Flow pattern determination Annex G (informative) Alternative rules for pressures in hoppers Annex H (informative) Actions due to dust explosions Background Documents and other supporting material Almost all Eurocodes represent the state-of-the-art in the respective scientific and technical field at the time of their drafting The scientific and technical basis of EN 1991 included mainly : - the systematic review of the existing relevant national codes and practices - consideration of relevant international standards (e.g. ISO Standards) or codes (e.g. JCSS Model Codes) - recent (prenormative) research results (e.g. European Snow Map) - calibration of load models based on probabilistic approaches and appropriate measurements (e.g. traffic loads for road bridges) Background Documents and other supporting material (cont.) - Well-established relevant international literature Strictly speaking, as Background Documents (BD) are considered all of the aforementioned material that has been taken into account by the relevant Project Team, during the drafting of the Eurocodes. All other relevant material, including literature, workshops and seminars, handbooks, guides and books or articles, are considered to be additional information and supporting material. A typical example are the 5 handbooks prepared in the framework of a Leonardo Da Vinci European Project (Handbook 3 is very closely linked to EN 1991, since it is dedicated to Action Effects on Buildings, and Handbook 4 is dedicated to the Design of Bridges ). This material is accessible on the Eurocodes website. Background Documents and other supporting material (cont.) The uploading of the Background Documents (BD) for EN 1991 is under way by the Secretary of EN/TC250/SC1. Until recently BD have been uploaded for the following Parts of EN 1991 : - EN EN EN EN EN and Handbooks 1 to 5 Additional information can also be found in the relevant websites, e.g. and other links (e.g. NSO et al.) Present and Future of the EN 1991 Finalising the preparation of some Corrigenda (target date June 2008) Detecting the eventual need for some Amendments (target date June 2009) On national level : Full implementation. Several countries have already issued their national standard EN 1991, but uploading of the NDPs in the ad-hoc data base of JRC Ispra goes on at a slow pace Prospects for the future : - Extending the snow map and other climatic data to cover the new EU Member States - Including eventually the ISO Standards on Waves and Currents and on Atmospheric Icing - Extending the Eurocodes to include glass and FRPs 6

13 THANK YOU FOR YOUR ATTENTION 7

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15 EN N. Malakatas Ministry of Environment, Physical Planning & Public Works of Greece

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17 Use of EN Eurocode 1: Actions on structures Part 1-1: General actions - Densities, self-weight, imposed loads for buildings Dr-Ing. Nikolaos E. Malakatas Head of Department - Ministry of Environment, Planning and Public Works - GREECE Chairman of CEN/TC250/SC1 Gives design guidance and actions for the structural design of buildings and civil engineering works, including the following aspects : - densities of construction materials and stored materials - self-weight of construction elements, and - imposed loads for buildings Is intended for Clients, Designers, Contractors and Public Authorities Is intended to be used with EN 1990 (Basis of Structural Design), other parts of EN 1991 (Actions) and EN 1992 to EN 1999 (Materials Eurocodes) for the design of structures. LINKS BETWEEN THE Programme of implementation of EN EN 1990 EN 1991 EN 1992 EN 1993 EN 1994 EN 1995 EN 1996 EN 1999 EN 1997 EN 1998 Structural safety, serviceability and durability Actions on structures Design and detailing Geotechnical and Seismic design Received positive vote as EN in April 2002 (Supersedes ENV : 1995) Published by CEN in July 2002 Confirmed in 2007 for a further period of 5 years Implementation on a national level in the Member States (National Standard EN and National Annex) still in process Withdrawal of conflicting standards probably by 2009/2010 Contents of EN Foreword Section 1 General Section 2 Classification of Actions Section 3 Design Situations Section 4 Densities of Construction and Stored Materials Section 5 Self-weight of Construction Works Section 6 Imposed Loads on Buildings Annex A (Informative) Tables for Nominal Density of Construction Materials, and Nominal Density and Angles of Repose for Stored Materials Annex B (Informative) Vehicle Barriers and Parapets for Car Parks Scope of EN Design guidance and actions for the structural design of buildings and civil engineering works, including: - densities of construction materials, additional materials for bridges and stored materials (Section 4 & Annex A), - self-weight of construction elements (Section 5), and - imposed loads for building floors and roofs (Section 6), according to category of use : - residential, social, commercial and administration areas; - garage and vehicle traffic areas (for gross vehicle weight < 160 kn); - areas for storage and industrial activity; - roofs; - helicopter landing areas. Actions on silos and tanks caused by water or other materials are dealt in EN Snow load on roofs is dealt in EN

18 Classification of actions Classification of actions (cont.) (Reminder from EN 1990) Variation in time: Permanent, Variable or Accidental Origin: Direct or Indirect Spatial Variation: Fixed or Free Nature and/or structural response: Static or Dynamic Self-weight of construction works: generally a Permanent Fixed action, however If Variable with time then represented by upper and lower characteristic values, and If Free (e.g. moveable partitions) then treated as an additional imposed load. Ballast and earth loads on roofs/terraces: Permanent with variations in properties (moisture content, depth) during the design life being taken into account. Classification of actions (cont.) Imposed loads (on buildings) : generally Variable Free actions, however loads resulting from impacts on buildings due to vehicles or accidental loads should be determined from EN Imposed loads for bridges are given in EN Also : Imposed loads generally Quasi-static actions and allow for limited dynamic effects in static structures, if there is no risk of resonance. Actions causing significant acceleration of structural members are classified as Dynamic and need to be considered via a dynamic analysis However for fork-lift trucks and helicopters additional inertial loads from hoisting and take-off/landing are accounted for through a dynamic magnification factor φ applied to appropriate static load values Design situations Permanent loads The total self-weight of structural and non-structural members is taken as a single action when combinations of actions are being considered Where it is intended to add or remove structural or nonstructural members after construction critical load cases need to be identified and taken into account. Water level is taken into account for relevant design situations, as is the source and moisture content of materials in buildings used for storage purposes. Design situations Imposed loads Probabilistic aspects Where areas are likely to be subjected to different categories of loadings, the critical load case needs to be identified and considered When imposed loads act simultaneously with other variable actions (e.g. wind, snow, cranes or machinery) the total of those imposed loads may be considered as a single action. However, for roofs of buildings, imposed loads should not be considered to act simultaneously with snow loads or wind actions. Self-weight may be usually determined as a product of the volume and the density, which both as random variables that may be described by normal distributions, with a mean value very close to their nominal value. Imposed loads are usually described by a Gumbel distribution, although Gamma distributions may also be used for the sustained (long-term) loads and exponential distributions for the intermittent (short-term) loads. 2

19 Densities of construction and stored materials Characteristic values of densities of construction and stored materials should generally be used. (If there is a significant scatter - e.g. due to their source, water content etc. an upper and a lower value should be used). Where only mean values are available, they should be taken as characteristic values in the design. Mean values for a large number of different materials are given in EN Annex A. For materials not in Annex A either: - the characteristic value of density needs to be determined in the National Annex, - a reliable direct assessment is carried out (eventually according to EN 1990 Annex D). Self-weight of construction works Generally represented by a single characteristic value calculated from nominal dimensions, characteristic values of densities and including, where appropriate, ancillary elements, e.g. non-structural elements and fixed services, weight of earth and ballast. Non-structural elements include : - roofing; - surfacing and coverings; - partitions and linings; - hand rails, safety barriers, parapets and curbs; - wall cladding; - suspended ceilings; - thermal insulation; - fixed services Self-weight of construction works (cont.) Fixed services include : - equipments for lifts and moving stairways; - heating, ventilating and air conditioning equipment; - electrical equipment; - pipes without their contents; - cable trunking and conduits Loads due to movable partitions are treated as imposed loads, but an equivalent uniformly distributed load may be used. Self-weight of construction works (cont.) Additional provisions specific for bridges : For ballast on railway bridges or fill above buried structures the upper and lower characteristic values of densities should be taken into account. The upper and lower characteristic values of the ballast depth should be considered as deviating from the nominal depth by ± 30%. The upper and lower characteristic values of the thickness due to waterproofing, surfacing and other coatings should be considered as deviating from the nominal value by ± 20% (if a post-execution coating is included in the nominal value) otherwise +40% and 20%, respectively. The upper and lower characteristic values of the self-weight of cables, pipes and service ducts should be considered as deviating from the mean value by ± 20%. Imposed loads on buildings Characteristic values of imposed loads for floors and roofs for the following types of occupancy and use: - residential, social, commercial and administration areas - garage and vehicle traffic - areas for storage and industrial activities - roofs - helicopter landing areas - barriers and walls having the function of barriers. Representation of actions Imposed loads on buildings are those arising from occupancy and the values given include : - normal use by persons; - furniture and moveable objects; - vehicles; - rare events such as concentrations of people and furniture, or the moving or stacking of objects during times of re-organisation and refurbishment Floor and roof areas in buildings are sub-divided into 11 categories according to use; loads specified are represented by uniformly distributed loads (UDL), concentrated loads, line loads or combinations thereof. Heavy equipment (e.g. in communal kitchens, radiology or boiler rooms) are not included in EN (To be agreed with the Client and/or the relevant Authority). 3

20 Main Categories of Use : Categories of use Residential, social, commercial and administration areas -4 categories (A, B, C and D) Areas for storage and industrial activities -2 categories (E1 and E2) Garages and vehicle traffic (excluding bridges) -2 categories (F and G) Roofs -3 categories (H, I and K) Residential, social, commercial and administration areas Table 6.1 Categories of use Category Specific use Example A Areas for domestic and Rooms in residential buildings and houses; residential activities bedrooms and wards in hospitals; bedrooms in hotels and hostels kitchens and toilets. B Office areas C Areas where people may congregate (with the exception of areas defined under category A, B and D 1) ) C1: Areas with tables, etc e.g. areas in schools, cafes, restaurants, dining halls, reading rooms, receptions C2: Areas with fixed seats, e.g. areas in churches, theatres or cinemas, conference rooms, lecture halls, assembly halls, waiting rooms, railway waiting rooms. C3: Areas without obstacles for moving people, e.g. areas in museums, exhibition rooms, etc. and access areas in public and administration buildings, hotels, hospitals, railway station forecourts C4:Areas with possible physical activities, e.g. dance halls, gymnastic rooms, stages. D Shopping areas D1: Areas in general retail shops C5:Areas susceptible to large crowds, e.g. in buildings for public events like concert halls, sports halls including stands, terraces and access areas and railway platforms. D2: Areas in department stores. 1) Attention is drawn to (2), in particular for C4 and C5. See EN 1990 when dynamic effects need to be considered. For Category E, see Table 6.3 NOTE 1. Depending on their anticipated uses, areas likely to be categorised as C2, C3, C4 may be categorised as C5 by decision of the client and/or National annex. Imposed loads on floors, balconies and stairs in buildings Additional loading from movable partitions Table 6.2 Imposed loads on floors, balconies and stairs in buildings Categories of loaded areas qk [kn/m 2 ] Category A - Floors 1,5 to 2,0 - Stairs 2,0 to 4,0 - Balconies 2,5 to 4,0 Category B Category C - C1 - C2 - C3 - C4 - C5 2,0 to 3,0 2,0 to 3,0 3,0 to 4,0 3,0 to 5,0 4,5 to 5,0 5,0 to 7,5 Qk [kn] 2,0 to 3,0 2,0 to 4,0 2,0 to 3,0 1, 5 to 4,5 3,0 to 4,0 2,5 to 7,0 (4,0) 4,0 to 7,0 3,5 to 7,0 3,5 to 4,5 Category D -D1 -D2 4,0 to 5,0 4,0 to 5,0 3,5 to 7,0 (4,0) 3,5 to 7,0 NOTE: Where a range is given in this table, the value may be set by the National annex. The recommended values, intended for separate application, are underlined. qk is intended for the determination of general effects and Qk for local effects. The National annex may define different conditions of use of this Table. Provided that a floor allows a lateral distribution of loads, the self-weight of movable partitions may be taken into account by a uniformly distributed load q k which should be added to the imposed loads of floors obtained from Table 6.2 (Cat. A to D). This load depends on the self-weight of the movable partitions, as follows : - self-weight < 1 kn/m, q k = 0,5 kn/m 2-1 kn/m < self-weight < 2 kn/m, q k = 0,8 kn/m 2-2 kn/m < self-weight < 3 kn/m, q k = 1,2 kn/m 2 Load arrangements Floors, beams and roofs Mid span bending moment of a floor structure Chess board arrangement Simplification in EN Load arrangements (cont.) For the design of a floor structure within one storey or a roof, the imposed load shall be applied as a free action at the most unfavourable part of the influence area. Effect of actions that cannot exist simultaneously should not be considered together (EN 1990). For the design of a column loaded from several storeys, load assumed to be distributed uniformly. For local verification concentrated load Q k acting alone should be considered. Reduction factors α A (for floors, beams and roofs) and α n (for columns and walls) may be applied, but factors ψ and α n should not be considered together. 4

21 Reduction factors α n and α A Factors ψ i α n 2 + ( n 2) ψ = n 0, α A 5 = ψ 7 0 A0 + A (Reminder from EN 1990) Actions ψ 0 ψ 1 ψ 2 α n 1 n) 0,90.9 ( n) 2( n0,8 ) 0.8 n) 0,70.7 n1) ČR (C, D) CEN, DE UK FR (C, D) 0,60.6 ( n) FR (A, B) 0,5 0.5 ČR (A, B) n α A 1 A) 0,90.9 N( A) N1( A) 0,80.8 ) A) 0,70.7 A) 1( A) 2( A0,6 ) 0.6 FI ČR (C, D) ČR (A, B) CEN DE (A, B) FR UK DE (C, D) A [m 2 ] 0, A Imposed Cat. A, B 0,7 0,5 0,3 Imposed Cat. C, D 0,7 0,7 0,6 Imposed Cat. E 1,0 0,9 0,8 Snow 0,5-0,7 0,2-0,5 0,0-0,2 Wind 0,6 0,2 0,0 Temperature 0,6 0,5 0,0 Reduction factor α A for floors A (m 2 ) α A (EN α A (EN with ψ o = 0,7) with ψ o = 1,0) 40 0,75 0, ,63 0, ,59 0, ,56 0, ,54 0,76 Reduction factor α n for columns n α A (EN with ψ o = 0,7) 1 1,00 2 1,00 3 0,90 4 0,85 5 0,82 6 0,80 7 0,79 8 0,78 9 0, ,76 Imposed loads on floors due to storage Actions induced by forklifts Table 6.3 Categories of storage and industrial use Category Specific Use Example E1 Areas susceptible to accumulation of goods, including access areas Areas for storage use including storage of books and other documents E2 Industrial use Table 6.4 Imposed loads on floors due to storage Categories of loaded areas q k [kn/m 2 ] Q k [kn] Category E1 7,5 7,0 NOTE The values may be changed if necessary according to the usage (see Table 6.3 and Annex A) for the particular project or by the National annex. qk is intended for the determination of general effects and Qk for local effects. The National annex may define different conditions of use of Table 6.4. Forklifts and transport vehicles Forklifts are classified into 6 classes via their hoisting capacity, which is reflected in other characteristics such as weight and plan dimensions. For each class, a static axle load is defined which is then increased by a dynamic (multiplication) factor φ dependent on whether the forklift has solid (φ = 2,00)or pneumatic (φ = 1,40) tyres. That factor is intended to account for the inertial effects caused by acceleration and deceleration of the hoisted load. Where transport vehicles move on floors, either freely or guided by rails, the actions need to be determined from the pattern of the vehicle s wheel loads. The static value of those wheel loads is determined from permanent weights and pay loads and the spectra of loads should be used to define appropriate combination factors and fatigue loads. 5

22 Actions induced by forklifts Garages and vehicle traffic areas Table 6.8 Imposed loads on garages and vehicle traffic areas Categories of traffic areas Category F Gross vehicle weight: 30kN Category G 30kN < gross vehicle weight 160 kn q k [kn/m 2 ] q k 5,0 Q k [kn] Q k Q k NOTE 1 For category F q k may be selected within the range 1,5 to 2,5 kn/m 2 and Q k may be selected within the range 10 to 20 kn. NOTE 2 For category G, Q k may be selected within the range 40 to 90 kn NOTE 3 Where a range of values are given in Notes 1 & 2, the value may be set by the National annex. The recommended values are underlined. Category F (e.g. garages, parking areas, parking halls) Category G (e.g. access routes, delivery zones, zones accessible to fire engines) Categorization of roofs Imposed loads on roofs of Cat. H Categories of loaded area (of a roof) : Category H Accessible for normal maintenance and repair only Category I Accessible with occupancy according to categories A to G Category K Accessible for special services e.g. helicopter landing areas Table 6.10 Imposed loads on roofs of category H Roof q k [kn/m 2 ] Q k [kn] Category H q k Q k NOTE 1 For category H q k may be selected within the range 0,0 to 1,0 kn/m2 and Q k may be selected within the range 0,9 to 1,5 kn. Where a range is given the values may be set by the National Annex. The recommended values are: q k = 0,4 kn/m 2, Q k = 1,0kN NOTE 2 q k may be varied by the National Annex dependent upon the roof slope NOTE 3 q k may be assumed to act on an area A which may be set by the National Annex. The recommended value for A is 10m 2, within the range of zero to the whole area of the roof. NOTE 4 See also (1) The minimum values given in Table 6.10 do not take into account uncontrolled accumulations of construction materials that may occur during maintenance Separate verifications to be performed for Q k and q k, acting independently Imposed loads on roofs of Cat. K for helicopters Horizontal loads on partition walls and parapets Table 6.11 Imposed loads on roofs of category K for helicopters Table 6.12 Horizontal loads on partition walls and parapets Loaded areas Category A qk [kn/m] qk Class of Helicopter Take-off load Q of helicopter Take-off load Q k Dimension of the loaded area (m x m) Category B and C1 Categories C2 to C4 and D Category C5 qk qk qk Category E qk HC1 HC2 Q 20 kn 20 kn < Q 60 kn Q k = 20 kn Q k = 60 kn 0,2 x 0,2 0,3 x 0,3 Category F See Annex B Category G See Annex B NOTE 1 For categories A,B and C1, qk may be selected within the range 0,2 to 1,0 (0,5) NOTE 2 For categories C2 to C4 and D qk may be selected within the range 0,8 kn/m to -1,0 kn/m The dynamic factor φ to be applied to the take-off load Q k to take account of impact effects may be taken as φ = 1,40 NOTE 3 For category C5, qk may be selected within the range 3,0 kn/m to 5,0 kn/m NOTE 4 For category E qk may be selected within the range 0,8 kn/m to 2,0 kn/m. For areas of category E the horizontal loads depend on the occupancy. Therefore the value of qk is defined as a minimum value and should be checked for the specific occupancy. NOTE 5 Where a range of values is given in Notes 1, 2, 3 and 4, the value may be set by the National Annex. The recommended value is underlined. NOTE 6 The National Annex may prescribe additional point loads Qk and/or hard or soft body impact specification for analytical or experimental verification. 6

23 Annex A (informative) : Nominal densities and angles of repose Table A.1 - Construction materials-concrete and mortar Table A.2 - Construction materials-masonry Table A.3 - Construction materials-wood Table A.4 - Construction materials-metals Table A.5 - Construction materials- other materials Table A.6 - Bridge materials Table A.7 - Stored materials - building and construction Table A.8 - Stored products agricultural Table A.9 - Stored products - foodstuffs Table A.10 - Stored products - liquids Table A.11 - Stored products - solid fuels Table A.12 - Stored products - industrial and general Annex B (informative) : Vehicle barriers and parapets for car parks The force in kn acting on 1,5 m of a barrier : δ c δ b m v F = 0,5 m v 2 / (δ c + δ b ) [kn] the deformation of the vehicle (mm) the deformation of the barrier (mm) the gross mass of the vehicle (kg) the velocity of the vehicle (m/s) 200 F [kn] 100 δ c =100 mm δ c =200 mm δ c =50 mm δ c For vehicles < 2500 kg: m = 1500 kg, v = 4,5 m/s, δ c = 100 mm. Backgound Documents and other supporting material Message for the near future A more general reference to Background Documents (BD) and related supporting material has been included and presented in the Introduction to EN The BD on the imposed loads on floors and roofs is already uploaded on the relevant website. Handbook 3 (Action Effects for Buildings) and Handbook 4 (Design of Bridges) of the Leonardo Da Vinci Pilot Project for the Development of Skills Facilitating the Implementation of Structural Eurocodes are considerd to be an appropriate first approach for the deeper understanding of EN Since a few years various books are being available (e.g. the Thomas Telford collection of Guides) Please try on a national level to finalise and issue the National Annex and upload the NDPs in the ad-hoc data base of JRC Ispra (if not already done so) THANK YOU FOR YOUR ATTENTION 7

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25 EN P. Formichi University of Pisa

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27 Brussels, February 2008 Dissemination of information workshop 1 Scope of the presentation Brussels, February 2008 Dissemination of information workshop 2 EN 1991 Eurocode 1: Actions on structures Part 1-3 General actions Snow Loads Paolo Formichi Department of Structural Engineering University of Pisa - Italy Description of EN Eurocode 1: Part 1-3: Snow Loads Background research for snow maps for Europe, Accidental (exceptional) loads, Shape Coefficients, Combination Factors, etc. Examples Background research Background research Brussels, February 2008 Dissemination of information workshop 3 Many clauses of EN are based on the results of a research work, carried out between 1996 and 1999, under a contract specific to this Eurocode, to DGIII/D3 of the European Commission. Brussels, February 2008 Dissemination of information workshop 4 The research results are contained in two final reports. They were identified four main research items: study of the European ground snow loads map investigation and treatment of exceptional snow loads study of conversion factors from ground to roof loads definition of ULS and SLS combination factors for snow loads. EN Field of application EN Field of application Brussels, February 2008 Dissemination of information workshop 5 Brussels, February 2008 Dissemination of information workshop 6 EN provides guidance for the determination of the snow load to be used for the structural design of buildings and civil engineering works for sites at altitudes under 1500m. In the case of altitudes above 1500m advice may be found in the appropriate National Annex. EN does not give guidance on the following specialist aspects of snow loading: impact loads due to snow sliding off or falling from a higher roof; additional wind loads resulting from changes in shape or size of the roof profile due to presence of snow or to the accretion of ice; loads in areas where snow is present all the year; loads due to ice; lateral loading due to snow (e.g. lateral loads due to dirfts); snow loads on bridges

28 Brussels, February 2008 Dissemination of information workshop 7 Contents of EN Classification of actions Foreword Section 1: General Section 2: Classification of actions Section 3: Design situations Section 4: Snow load on the ground Section 5: Snow load on roofs Section 6: Local effects ANNEX A: Design situations and load arrangements to be used for different locations ANNEX B: Snow load shape coefficients for exceptional snow drifts ANNEX C: European Ground Snow Load Maps ANNEX D: Adjustment of the ground snow load according to return period ANNEX E: Bulk weight density of snow Brussels, February 2008 Dissemination of information workshop 8 Actions due to snow are classified, in accordance with EN 1990, as: Variable: action for which the variation in magnitude with time is neither negligible nor monotonic Fixed: action that has a fixed distribution and position over the structure. Static: action that does not cause significant acceleration of the structure or structural members Classification of actions Definition of Exceptional snow load on the ground Brussels, February 2008 Dissemination of information workshop 9 Brussels, February 2008 Dissemination of information workshop 10 For particular conditions may be treated as accidental actions: action, usually of short duration but of significant magnitude, that is unlikely to occur on a given structure during the design working life Exceptional snow load on the ground load of the snow layer on the ground resulting from a snow fall which has an exceptionally infrequent likelihood of occurring Exceptional snow load on the ground Exceptional snow drifts Exceptional snow load on the ground Exceptional snow load on the ground Brussels, February 2008 Dissemination of information workshop 11 In some regions, particularly southern Europe, isolated very heavy snow falls have been observed resulting in snow loads which are significantly larger than those that normally occur. Including these snowfalls with the more regular snow events for the lengths of records available may significantly disturb the statistical processing of more regular snowfalls Gumbel probability paper: Pistoia (IT) N of recorded years = 51 N of no snowy winters = 26 s m = Max. snow Load = 1.30 kn/m 2 50yrs load incl. Max Load = 1.00 kn/m 2 s k = 50yrs load excluded Max Load = 0.79 kn/m 2 k = s m /s k = 1,65 Brussels, February 2008 Dissemination of information workshop 12 The National Annex should specify the geographical locations where exceptional ground snow loads are likely to occur.? When the maximum ground snow load is to be considered as exceptional? If the ratio of the largest load value to the characteristic load determined without the inclusion of that value is greater than 1.5 then the largest value should be treated as an exceptional value According to this definition over 2600 weather stations from 18 CEN countries (1997), in 159 they were registered exceptional ground snow loads.

29 Brussels, February 2008 Dissemination of information workshop 13 Definition of Exceptional snow drift Design Situations Exceptional snow drift load arrangement which describes the load of the snow layer on the roof resulting from a snow deposition pattern which has an exceptionally infrequent likelihood of occurring These load arrangements (treated in Annex B of EN ) may result from wind redistribution of snow deposited during single snow events. Localised snow concentrations may develop at obstructions and abrupt changes in height, leaving other areas of the roof virtually clear of snow. Brussels, February 2008 Dissemination of information workshop 14 Different climatic conditions will give rise to different design situations. The four following possibilities are identified: - Case A: normal case (non exceptional falls and drifts) - Case B1: exceptional falls and non exceptional drifts - Case B2: non exceptional falls and exceptional drifts - Case B3: exceptional falls and drifts. The national competent Authority may choose in the National Annex the case applicable to particular locations for their own territory. Design Situations Snow load on the ground Brussels, February 2008 Dissemination of information workshop 15 Brussels, February 2008 Dissemination of information workshop 16 Section 4 of EN Snow load on the ground Accidental: refers only to exceptional conditions Persistent: Conditions of normal use Transient: temporary conditions (e.g. execution or repair) Snow load on the ground Snow load on the ground Brussels, February 2008 Dissemination of information workshop 17 The snow load on the roof is derived from the snow load on the ground, multiplying by appropriate conversion factors (shape, thermal and exposure coefficients). Brussels, February 2008 Dissemination of information workshop 18 s k is intended as the upper value of a random variable, for which a given statistical distribution function applies, with the annual probability of exceedence set to 0,02 (i.e. a probability of not being exceeded on the unfavourable side during a reference period of 50 years). For locations where exceptional ground snow loads are recorded, these value must be excluded from the data sample of the random variable. The exceptional values may be considered outside the statistical methods. The characteristic ground snow loads (s k ) are given by the National Annex for each CEN country.

30 Brussels, February 2008 Dissemination of information workshop 19 Snow load on the ground Snow load on the ground Needs for harmonization Development of European ground snow load map Inconsistencies at borders between existing national maps; Different procedures for measuring snow load (mainly ground snow data): snow depths + density conversion, water equivalent measures, direct load measures; Different approaches for statistical data analysis (Gumbel, Weibull, Log-normal distributions). The research developed a consistent approach Produced regional maps (Annex C of EN ) Snow load with Altitude relationship Zone numbers & altitude functions Geographical boundaries! Brussels, February 2008 Dissemination of information workshop 20 For maps in Annex C of EN the following common approach has been followed: Statistical analysis of yearly maxima, using the Gumbel Type I CDF (best fitting in the majority of data points); LSM for the calculation of the best fitting regression curve; Both zero and non zero values have been analysed according to the mixed distribution approach ; Approximately 2600 weather stations consistently analysed; Regionalization of CEN area (18 countries 1997) into 10 climatic regions; Smoothing of maps across borderlines between neighbouring climatic regions (buffer zones 100 km). Snow load on the ground Snow load on the ground Brussels, February 2008 Dissemination of information workshop European regions, with homogeneous climatic features Brussels, February 2008 Dissemination of information workshop 22 Alpine Region Snow load at sea level (France, Italy, Austria, Germany and Switzerland) Snow load on the ground Snow load on the ground Brussels, February 2008 Dissemination of information workshop 23 Zone 4 Brussels, February 2008 Dissemination of information workshop 24 Alpine Region Snow load at sea level Zone 3 Zone 2 Zone 1 z = Zone number given on the map A = site altitude above Sea Level [m]

31 Brussels, February 2008 Dissemination of information workshop 25 Snow load on the ground Snow load on the ground - Example Brussels, February 2008 Dissemination of information workshop 26 Map for Mediterranean region Annex C EN (geographical boundaries) Zone 1 Med. Zone 1 Alp. Zone 2 Zone 3 Italian National Annex (administrative boundaries) Italian ground Snow load Map: - 4 different zones (3 Med. + 1 Alpine) - Administrative boundaries (110 provinces) - 4 Altitude correlation functions Ground Snow Load kn/m Zone 1 alp Zone 1 med Zone 2 Zone Altitude [m] Example of calculation of ground snow load at a given location: Inputs: - zone n. 3 - altitude = 600m a.s.l. s k = 1,30 kn/m 2 Other representative values of ground snow loads Other representative values of ground snow loads Brussels, February 2008 Dissemination of information workshop 27 Brussels, February 2008 Dissemination of information workshop 28 j 1 Combination valueψ 0 s k γ "+" γ Q,iψ 0,iQ G, jgk, j γ PP"+" γ Q,1Qk,1"+" i>1 k,i Eq EN 1990 Frequent value ψ 1 s k The frequent value ψ 1 s k is chosen so that the time it is exceeded is 0,10 of the reference period. Gk, "+" P"+" ψ Q "+" ψ 2,iQ j 1,1 k,1 j 1 i> 1 k,i Eq. 6.15b EN 1990 The combination factor ψ 0 is applied to the snow load effect when the dominating load effect is due to some other external load, such as wind. Based upon the available data ψ 0 values were calculated through the Borges-Castanheta method. Quasi-permanent value ψ 2 s k The quasi-permanent value ψ 2 s k (used for the calculation of long-term effects) is usually chosen so that the proportion of the time it is exceeded is 0,50 of the reference period. ψ 1 and ψ 2 values were calculated from daily data series available at 59 weather stations representative of all 10 different climatic regions. Gk, "+" P"+" ψ 2,iQ j j 1 i> 1 k,i Eq. 6.16b EN 1990 Other representative values of ground snow loads Treatment of exceptional loads on the ground Brussels, February 2008 Dissemination of information workshop 29 Brussels, February 2008 Dissemination of information workshop 30 Maps given in National Annexes are determined without taking into account exceptional falls? How to determine design values for accidental ground snow loads? For locations where exceptional loads may occur (National Annex), the ground snow load may be treated as accidental action with the value: s Ad = C esl s k Where: C esl (set by the National Annex) - recommended value = 2,0 s k = characteristic ground snow load at the site considered Gk, j"+" P"+"Ad"+"( ψ 1,1 orψ 2,1) Qk,1"+" ψ 2,iQk,i Eq. 6.11b j 1 i> 1 EN 1990

32 Brussels, February 2008 Dissemination of information workshop 31 Snow load on roofs Snow load on roofs Section 5 of EN Snow load on roofs Brussels, February 2008 Dissemination of information workshop 32 The snow the snow layers on a roof can have many different shapes depending on roof s characteristics: its shape; its thermal properties; the roughness of its surface; the amount of heat generated under the roof; the proximity of nearby buildings; the surrounding terrain; the local meteorological climate, in particular its windiness, temperature variations, and likelihood of precipitation (either as rain or as snow). Snow load on roofs Load arrangements Snow load on roofs Load arrangements Brussels, February 2008 Dissemination of information workshop 33 In absence of wind, or with very low wind velocities (<2 m/s) snow deposits on the roof in a balanced way and generally a uniform cover is formed UNDRIFTED LOAD ARRANGEMENT Brussels, February 2008 Dissemination of information workshop 34 With wind speeds in the range of 4 to 5 m/s, much of the snow is deposited in areas of aerodynamic shade DRIFTED SNOW LOAD ARRANGEMENT Aerodynamic shade wind wind Model in wind tunnel wind velocity of 4m/s Snow load on roofs Load arrangements Snow load on roofs Load arrangements Brussels, February 2008 Dissemination of information workshop 35 For situations where the wind velocity increases above 4 5 m/s snow particles can be picked up from the snow cover and redeposited on the lee sides, or on lower roofs in the lee side, or behind obstructions on the roof. DRIFTED SNOW LOAD ARRANGEMENT wind Brussels, February 2008 Dissemination of information workshop 36 EXCEPTIONAL DRIFTS In maritime climates (e.g. UK and Eire), where snow usually melts and clears between the individual weather systems and where moderate to high wind speeds occur during the individual weather system, the amount of the drifted load is considered to be of a high magnitude compared to the ground snow load, and the drifted snow is considered an exceptional load and treated as an accidental load using the accidental design situation (Annex B of EN ). wind Model in wind tunnel for multi - pitched roof wind velocity > 5 m/s Model in wind tunnel for multi - pitched roof wind velocity > 5 m/s

33 Brussels, February 2008 Dissemination of information workshop 37 w Snow load on roofs Snow load on roofs Load arrangements Brussels, February 2008 Dissemination of information workshop 38 Snow load on the roof (s) is determined converting the characteristic ground snow load into an undrifted or drifted roof load for persistent/transient and, where required by the National Annex, accidental design situations by the use of: an appropriate shape coefficient which depends on the shape of the roof; considering the influence of thermal effects from inside the building and the terrain around the building. For the persistent / transient design situations i.e. no exceptional snow falls or drifts: s = μ i C e C t s k (5.1 EN ) For the accidental design situations, where exceptional ground snow load is the accidental action: s = μ i C e C t s Ad (5.2 EN ) For the accidental design situations where exceptional snow drift is the accidental action and where Annex B applies: s = μ i s k (5.3 EN ) Snow load on roofs Shape coefficients Snow load on roofs Shape coefficients Brussels, February 2008 Dissemination of information workshop 39 EN gives shape coefficients for the following types of roofs (non exceptional drifted cases): Brussels, February 2008 Dissemination of information workshop 40 Annex B of EN gives shape coefficients for the following types of roofs (exceptional drifted cases): Multi-span Monopitch Pitched Cylindrical Roofs abutting and close to taller construction works Roofs abutting and close to taller construction works Drifting at projections, obstructions and parapets Multi-span Snow load on roofs Shape coefficients Snow load on roofs Shape coefficients Brussels, February 2008 Dissemination of information workshop 41 Values for shape coefficients μ i given in EN are calibrated on a wide experimental campaign, both in situ and in wind tunnel. 1,49 1,92 Average = 1,67 Brussels, February 2008 Dissemination of information workshop 42 Roof abutting and close to taller construction works μ s is for snow falling from the higher roof (α>15 ) μ w is the snow shape coefficient due to wind: μ w = (b 1 +b 2 )/2h < γ h /s k γ = 2 kn/m < μ w < 4 l s = 2h 5m < l s < 15m 10,00 9,00 30 wind μ w 8,00 7,00 6,00 5,00 4,00 3,00 b 1 = 8,0 m b 2 = 10,0 m s k = 0,8 kn/m 2 2,00 1,00 Multi-span drifted case 0,00 0,0 1,0 2,0 3,0 4,0 5,0 6,0 7,0 8,0 h [m]

34 Brussels, February 2008 Dissemination of information workshop 43 Snow load on roofs Exposure coefficient Snow load on roofs Exposure coefficient Brussels, February 2008 Dissemination of information workshop 44 A coefficient (C e ) defining the reduction or increase of snow load on a roof of an unheated building, as a fraction of the characteristic snow load on the ground. The choice for C e should consider the future development around the site. C e should be taken as 1,0 unless otherwise specified for different topographies. The National Annex may give the values of C e for different topographies, recommended values are given. Windswept topography, where (C e = 0,8 ) are flat unobstructed areas exposed on all sides without, or little shelter afforded by terrain, higher construction works or trees. Normal topography, where (C e = 1,0 ) areas where there is no significant removal of snow by wind on construction work, because of terrain, other construction works or trees. Sheltered topography, where (C e = 1,2 ) areas in which the construction work being considered is considerably lower than the surrounding terrain or surrounded by high trees and/or surrounded by higher construction works. Snow load on roofs Thermal coefficient Snow load on roofs Example (1) Brussels, February 2008 Dissemination of information workshop 45 Brussels, February 2008 Dissemination of information workshop 46 Multi-span roof in Sweden The thermal coefficient C t is used to account for the reduction of snow loads on roofs with high thermal transmittance (> 1 W/m 2 K), in particular for some glass covered roofs, because of melting caused by heat loss. For all other cases: C t = 1,0 Further guidance may be obtained from ISO Properties of the building: Location: Sweden - Snow load zone 2, alt. 300 m a.s.l. Normal conditions: no exceptional falls, no exceptional drifts Building surroundings: normal C e = 1,0 Effective heat insulation applied to roof: C t = 1,0 Snow load on roofs Example (2) Snow load on roofs Example (3) Brussels, February 2008 Dissemination of information workshop 47 A Altitude relationship for Sweden: s k = 0,790Z + 0, where: Z is the Zone Number & A is the altitude Brussels, February 2008 Dissemination of information workshop 48 Determination of shape coefficients: Undrifted load arrangement: Case (i) μ 1 Drifted load arrangement: Case (ii) μ 1, μ 2 Zone 2 A = 300 m µ µ2 µ1 Characteristic ground snow load at the site: s k = 0,790 x 2 + 0, /336 = 2,85 kn/m α α = 40 1 α = 30 2 α1 + α = 2 μ1( α1) = 0,53 μ1( α 2 ) = 0,80 α 2 = 35 μ α ( ) = 1, 60 2

35 Brussels, February 2008 Dissemination of information workshop 49 Snow load on roofs Example (4) Local Effects s k = 2,85 kn/m 2 s = C t C e μ i s k α1 = 40 μ1( α1) = 0,53 α 2 = 30 μ1( α2 ) = 0,80 α1 + α 2 α = = 35 μ2 α = 1, 2 ( ) 60 Combination coefficients Climatic region: Finland, Iceland, Norway Sweden: ψ 0 = 0,70 ψ 1 = 0,50 ψ 2 = 0,20 Case (i) 1,51 kn/m 2 Case (ii) 1,51 kn/m 2 2,28 kn/m ,51 kn/m 2 4,56 kn/m 2 2,28 kn/m 2 2,28 kn/m 2 Brussels, February 2008 Dissemination of information workshop 50 In addition to snow deposition patterns adopted for the global verification of the building, local verifications have to be performed for specific structural elements of the roof or roof s parts. Section 6 of EN gives the forces to be considered for the verification of: drifting at projections and obstructions; the edge of the roof; snow fences. The National Annex may be specify condition of use of this part or different procedures to calculate the forces. Local Effects Annexes Brussels, February 2008 Dissemination of information workshop 51 Drifting at projections and obstructions μ 1 = 0,8 μ 2 = γ h/s k where 0,8 μ 2 2,0 γ = 2 kn/m 3 (weight density of snow) l s = 2h 5 l s 15 m Brussels, February 2008 Dissemination of information workshop 52 Normative Annexes Annex A Design situations and load arrangements to be used for different locations Snow overhanging the edge of a roof (recommended for sites above 800 m a.s.l.) s e =k s 2 / γ where γ = 3 kn/m 3 γk = 3 /d < d γ (National Annex) d is in meters Annex B Snow load shape coefficients for exceptional snow drifts Annexes Further developments Brussels, February 2008 Dissemination of information workshop 53 Informative Annexes Brussels, February 2008 Dissemination of information workshop 54 Research needs for further developments Annex C European Ground snow load maps Majority produced during European Research project Annex D Adjustment of ground snow load for return period Expression for data which follow a Gumbel probability distribution Annex E Densities of snow Indicative density values for snow on the ground 1. Examine National Annex maps with the maps of Annex C of EN as a first step to obtain a harmonised snow map of Europe by ensuring consistency at borders; 2. Enlargement of the European ground snow load map to cover all the 29 Member States of the EU and EFTA; 3. Influence of roof dimensions on roof shape coefficients 4. Snow loading on glass structures; 5. Freezing/melting effects.

36 Brussels, February 2008 Dissemination of information workshop 55 Thank you for your attention

37 EN S. O. Hansen Svend Ole Hansen ApS

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39 Brussels, February 2008 Dissemination of information workshop 1 EN 1991 Eurocode 1: Actions on structures Your logo EN :2005 Contents Brussels, February 2008 Dissemination of information workshop 2 1. General EN :2005 Wind actions 2. Design situations 3. Modelling of wind actions 4. Wind velocity and velocity pressure 5. Wind actions 6. Structural factor 7. Pressure and force coefficients 8. Wind actions on bridges EN :2005 Contents Section 1 General 1.1 Scope Brussels, February 2008 Dissemination of information workshop 3 Brussels, February 2008 Dissemination of information workshop 4 Annex A. Terrain effects B. Procedure 1 for determining the structural factor C. Procedure 2 for determining the structural factor D. Structural factors for different types of structures E. Vortex shedding and aeroelastic instabilities F. Dynamic characteristics of structures (2) This Part is applicable to: - Buildings and civil engineering works with heights up to 200 m - Bridges having no span greater than 200 m, provided that they satisfy the criteria for dynamic response (3) This part is intended to predict characteristic wind actions on land-based structures, their components and appendages Section 1 General 1.1 Scope Section 2 Design situations Brussels, February 2008 Dissemination of information workshop 5 Brussels, February 2008 Dissemination of information workshop 6 Draft corrigendum to EN : January 2008 (11) Guyed masts and lattice towers are treated in EN and lighting columns in EN 40 (12) This part does not give guidance on the following aspects: - torsional vibrations, e.g. tall buildings with a central core - bridge deck vibrations from transverse wind turbulence - wind actions on cable supported bridges - vibrations where more than the fundamental mode needs to be considered (1)P The relevant wind actions shall be determined for each design situation identified in accordance with EN 1990, 3.2. (2) Traffic, snow and ice (3) Execution (4) Where in design windows and doors are assumed to be shut under storm conditions, the effect of these being open should be treated as an accidental design situation

40 Brussels, February 2008 Dissemination of information workshop 7 Section 3 Modelling of wind actions Section 4 Wind vel. and vel. pres Basic values Brussels, February 2008 Dissemination of information workshop Nature 3.2 Representations of wind actions 3.3 Classification of wind actions (1) Unless otherwise specified, wind actions should be classified as variable fixed actions v b c dir c season v b,0 3.4 Characteristic values (1) Note: All coefficients or models, to derive wind actions from basic values, are chosen so that the probability of the calculated wind actions does not exceed the probability of these basic values 3.5 Models Section 4 Wind vel. and vel. pres Basic values Norway: Basic wind velocity. NS :2002 Brussels, February 2008 Dissemination of information workshop 9 Brussels, February 2008 Dissemination of information workshop 10 ENV :1995 UK: Basic wind velocity. BS :1997 Faroe Islands extreme winds Brussels, February 2008 Dissemination of information workshop 11 Brussels, February 2008 Dissemination of information workshop 12

41 Brussels, February 2008 Dissemination of information workshop 13 Faroe Islands extreme winds Faroe Islands measuring stations Brussels, February 2008 Dissemination of information workshop 14 Vindklima i Danmark og i udlandet 29 Faroe Islands - Glyvursnes Faroe Islands basic wind velocities Brussels, February 2008 Dissemination of information workshop 15 Brussels, February 2008 Dissemination of information workshop 16 Vindklima i Danmark og i udlandet 37 Italy - Messina Southerly winds at Messina bridge deck height Brussels, February 2008 Dissemination of information workshop 17 Brussels, February 2008 Dissemination of information workshop 18

42 Brussels, February 2008 Dissemination of information workshop 19 Basis for updated European wind map? Climatological changes? Brussels, February 2008 Dissemination of information workshop 20 ENV :1995 Influence of terrain - measured wind velocities Section 4.3 Mean wind Brussels, February 2008 Dissemination of information workshop 21 Brussels, February 2008 Dissemination of information workshop 22 v m ( z) c ( z) c ( z) v r o b Section Terrain roughness Terrain categories and terrain parameters Brussels, February 2008 Dissemination of information workshop 23 Brussels, February 2008 Dissemination of information workshop 24 c ( z) k ln( z / z ) r r 0 k r z0 0,19 z0, II 0,07 z 0, II 0,05m

43 Brussels, February 2008 Dissemination of information workshop 25 Annex A: Terrain category I and II Annex A: Terrain category III and IV Brussels, February 2008 Dissemination of information workshop 26 Annex A: Terrain category 0 coastal area Coastal area exposed to the open sea Brussels, February 2008 Dissemination of information workshop 27 Brussels, February 2008 Dissemination of information workshop 28 Figure Assessment of terrain roughness A.2 Transition between roughness categories Brussels, February 2008 Dissemination of information workshop 29 Brussels, February 2008 Dissemination of information workshop 30

44 Brussels, February 2008 Dissemination of information workshop 31 A.2 Transition between roughness categories A.3 Terrain orography. Figure A.1 Brussels, February 2008 Dissemination of information workshop 32 Procedure 1 If the structure is situated near a change of terrain roughness at a distance: - less than 2 km from the smoother category 0 - less than 1 km from the smoother categories I to III the smoother terrain category in the upwind direction should be used. Small areas (less than 10% of the area under consideration) with deviating roughness may be ignored. Section 4.4 Wind turbulence. Turbulence intensity Section 4.5 Peak velocity pressure, peak velocity Brussels, February 2008 Dissemination of information workshop 33 Brussels, February 2008 Dissemination of information workshop 34 I v ( z) 1 c o ki ln( z / z 0 ) q p ( z) (1 7 I v ( z)) 1 2 v 2 m ( z) v p ( z) 1 7 I v ( z) v m ( z) Measured wind velocities Section 5 Wind actions 5.1 General Brussels, February 2008 Dissemination of information workshop 35 Brussels, February 2008 Dissemination of information workshop 36

45 Brussels, February 2008 Dissemination of information workshop 37 Section 5.2 Wind pressure on surfaces Figure 5.1 Pressure on surfaces Brussels, February 2008 Dissemination of information workshop 38 w e q ( z ) c p e pe w i q ( z ) c p i pi Section 7.2 Pressure coeff. for buildings. Figure 7.2 Section Vertical walls. Figure 7.5 Brussels, February 2008 Dissemination of information workshop 39 Brussels, February 2008 Dissemination of information workshop 40 Section Vertical walls. Table 7.1 Section Duopitch roofs. Figure 7.8 Brussels, February 2008 Dissemination of information workshop 41 Brussels, February 2008 Dissemination of information workshop 42

46 Brussels, February 2008 Dissemination of information workshop 43 Section Duopitch roofs. Table 7.4a Section 5.3 Wind forces Brussels, February 2008 Dissemination of information workshop 44 F w c c c q ( z ) A s d f p e ref Section 6 Structural factor Annex D Structural factor Brussels, February 2008 Dissemination of information workshop 45 Brussels, February 2008 Dissemination of information workshop Determination of structural factor The structural factor may be taken as 1 for a) buildings with a height less than 15 m b) facade and roof elements having a natural frequency greater than 5 Hz c) framed buildings which have structural walls and which are less than 100 m high and whose height is less than 4 times the in-wind depth d) chimneys with circular cross-sections whose height is less than 60 m and 6,5 times the diameter Annex D Structural factor Annex D Structural factor Brussels, February 2008 Dissemination of information workshop 47 Brussels, February 2008 Dissemination of information workshop 48

47 Brussels, February 2008 Dissemination of information workshop 49 Annex D Structural factor Brussels, February 2008 Dissemination of information workshop 50 Annex D Structural factor Brussels, February 2008 Dissemination of information workshop 51 Section 6 Structural factor. Figure 6.1 Brussels, February 2008 Dissemination of information workshop 52 Section 6.3 Detailed procedure ) ( 7 1 ) ( 2 1 ) ( 7 1 ) ( 7 1 ) ( 7 1 ) ( 2 1 B z I R B z I k c z I B z I c z I R B z I k c c s v s v p d s v s v s s v s v p d s Brussels, February 2008 Dissemination of information workshop 53 Backgrund turbulence and resonance turbulence Brussels, February 2008 Dissemination of information workshop 54 Wind vortices versus structural size

48 Brussels, February 2008 Dissemination of information workshop 55 Procedure 1 (dotted line) versus theory (solid line) Procedure 2 (dotted line) versus theory (solid line) Brussels, February 2008 Dissemination of information workshop 56 Structural factor. Procedure 1 or 2? Annex E Vortex shedding Brussels, February 2008 Dissemination of information workshop 57 Brussels, February 2008 Dissemination of information workshop 58 Procedure 2 has a more accurate representation of the theoretical background compared to procedure 1 Chimneys Bridges Annex E Vortex shedding. Bending vibrations Annex E Vortex sheding. Ovalling vibrations Brussels, February 2008 Dissemination of information workshop 59 Brussels, February 2008 Dissemination of information workshop 60

49 Brussels, February 2008 Dissemination of information workshop 61 Annex E Vortex shedding. Critical wind velocity Vortex shedding. Chimneys Brussels, February 2008 Dissemination of information workshop 62 v crit, i b n St i, y v crit, i b n i, o 2 St Vortex shdding. Chimneys Approach 1 versus approach 2 Brussels, February 2008 Dissemination of information workshop 63 Brussels, February 2008 Dissemination of information workshop 64 Approach 1: Vortex-resonance model Approach 2: Spectral model Turbulence is an active parameter only in approach 2 E1.5.1 General (3) Approach 2 allows for the consideration of different turbulence intensities, which may differ due to meteorological conditions. For regions where it is likely that it may become very cold and stratified flow condition may occur (e.g. in coastal areas in Northern Europe), approach 2 may be used. Vortex shedding. Bridge cross section Vortex shedding. Bridge cross section. Approach 1 Brussels, February 2008 Dissemination of information workshop 65 Brussels, February 2008 Dissemination of information workshop 66

50 Brussels, February 2008 Dissemination of information workshop 67 Vortex shedding. Bridge cross section. Approach 2 Vortex shedding. Approach 1 or 2? Brussels, February 2008 Dissemination of information workshop 68 Approach 2 has a more accurate representation of the physical phenomenon compared to approach 1

51 EN M. Holicky Czech Technical University in Prague

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53 EN Thermal Actions Milan Holický and Jana Marková, Czech Technical University in Prague DAV , Conversion of ENV (23 NDP) General Classification of actions Design situations Representation of actions Temperature changes in buildings Temperature changes in bridges Temperature changes in industrial chimneys, pipelines, etc. Annexes A Isotherm of national temperatures (normative) B Temperature differences in bridges decks (normative) C Coefficients of linear expansions (informative) D Temperature effects in buildings (informative) PPT file include 24 basic slides and additional (informative) slides. Background documents - Background Document of New European Code for Thermal Actions, Report No. 6, Pisa, Italy, Luca Sanpaolesi, Stefano Colombini, Thermal Actions on Buildings, Department of Structural Engineering, University of Pisa, Italy, Chapter 4 of Handbook 3, Leonardo da Vinci project CZ/02/B/F/PP , EN ISO 6946, Building components and building elements Thermal resistance and thermal transmittance Calculation methods, EN ISO 13370, Thermal performance of buildings Heat transfer via the ground Calculation methods, ISO Technical Report 9492, Bases for Design of Structures Temperature Climatic Actions, Emerson, M., TRRL Report 696, Bridge temperatures estimated from shade temperatures, UK, JCSS, Probabilistic Model Code, Zurich Eurocodes: Background and Applications 2 Collapse of the terminal E2 in Paris Scheme of the collapse Eurocodes: Background and Applications 3 Progressive weakening partly due to cracking during cycles of differential 4 thermal movements between concrete shell and curved steel member Eurocodes: Background and Applications Bridge in transient design situation Eurocodes: Background and Applications 5 Basic principles and rules - temperature changes are considered as variable and indirect actions - characteristic values have probability of being exceeded 0,02 by annual extremes (return period of 50 years) - the maximum and minimum shade air temperature measured by thermometers in a Stevenson Screen by the National Meteorological Service of each Member State - thermal actions shall be considered for both persistent and transient design situations - in special cases temperature changes in accidental design situations should be also verified Eurocodes: Background and Applications 6 1

54 An example: map of maximum temperatures in CR Maximum shade air temperatures of being exceeded by annual extremes with the probability of 0,02. Tmin = 32,1 C Tmax = 40,0 C mean µt = 37,4 C 32,1 to 34 C 34,1 to 36 C 36,1 to 38 C 38,1 to 40 C Temperature changes in buildings Thermal actions on buildings shall be considered when ultimate or serviceability limit state s may be affected. Effect of thermal actions may be influenced by nearby buildings, the use of different materials, structural shape and detailing. Three basic components are usually considered: - a uniform component T u T u = T T 0 - temperature difference T M - temperature differences of different structural parts T p Inner temperatures in buildings Outer temperatures T out Season summer winter Recommended inner temperatures in the Czech National Annex - summer 25 C - winter 20 C Temperature T in in 0 C T 1 (20 C) T 2 (25 C) Season Relative absorptivity Temperature T out in 0 C 0,5 bright light surface summer 0,7 light coloured surface 0,9 dark surface winter T max + T 3 T max + T 4 T max + T 5 T min N, E, N-E S, W, S-W and H Recommended values: T 3 0 C 18 C T 4 2 C 30 C T 5 4 C 42 C Uniform design temperatures in a building An thermally unprotected steel structure ČSN : T N = 60 C T e,min = -30 C T Nd = 60 1,2 = 72 C T e,max = 30 C An example of a fixed member T Nd =(44 10) 1,5=51 C q[kn/m] ČSN P ENV : T N = 61 C T e,min = -24 C T e,max = 37 C T Nd = 61 1,4 = 85 C ČSN EN : in Prague for dark surface and North-East T N = 76 C T e,min = -32 C T e,max = 40 + T 5 = 44 C T Nd = 76 1,5 = 114 C Material Concrete Steel Linear expansion α T 10-6 C Strain ε T ,51 0,61 Young modulus E MPa Stress σ T MPa Eurocodes: Background and Applications Eurocodes: Background and Applications 12 2

55 A uniform temperature component Annex D: temperatures in buildings - National maps of isotherms T max, T min - Effective temperatures in bridges graphical tools Maximum and minimum effective temperatures T T N,con = T 0 - T e,min T N,exp = T e,max - T 0 The total range T N = T e,max - T e,min R( x) T( x) = Tin ( Tin Tout ) R R Temperatures tot Thermal resistance [m 2 K/W] h i tot = Rin + + i λ i h ( ) = R + i in i λi R x R out C T in inner surface T(x) where λ [W/(mK)] is thermal conductivity T out x X outer surface A frame under a uniform component and different support conditions Eurocodes: Background and Applications 14 Three layers wall - graphical method Three layers wall EXCEL sheet Input temperatures Ti= 20 To= -20 Heat flow Q= 17,323 Transfer coef. Thermal conduct. Thickness Resistance Temperatures Layer Material W/m 2 / C W/m/ C m C Inside 20 0 Surface 0,111 18, Gypsum 0,081 16,668 0,16 0,013 2 Insulation 0,025 0,05 2,000-17,979 3 Brick 1,5 0,1 0,067-19,134 4 Outside 0,050-20, The total resistance of wall Rtot = 2, Eurocodes: Background and Applications Graph x temp 10-0,02 20, , ,013 16,668-0, ,05 0,1 0,15 0,2 0,063-17, ,163-19, ,183 Eurocodes: -20,000 Background and Applications Temperature changes in bridges Three types of bridge superstructures are considered 1. Steel deck steel box girder steel truss or plate girder 2. Composite deck 3. Concrete deck concrete slab concrete beam concrete box girder Basic temperature components a uniform component vertical temperature differences horizontal temperature differences approach 1 - linear approach 2 - non-linear Uniform effective temperatures Te,max Te,min maximum 70 Type 1 60 Type 2 Type Type 1 Te,max = Tmax + 16 C T 30 e,min = Tmin 3 C Type 2 Te,max = Tmax + 4,5 C for 30 C 50 C 4,5 C for 50 C 0 C 20 Tmax Te,min = Tmin + T min Type 3 Type 3 Te,max = Tmax + 1,5 C Type 2 8 C 10 Te,min = Tmin + 0 Type Tmax Tmin -50 minimum

56 Approach 1: linear vertical differences T M,heat ( o C) T M,cool ( o C) Type 1, steel Approach 2: non-linear vertical difference Type 1 (steel) Type 2, composite Type 3, concrete box girder beam slab Thickness of surfacing considered by reduction coefficient k sur. Approach 2: non-linear vertical differences Temperature differences Type 2 (composite) (a) heating (b) cooling Approach 2: non-linear vertical differences Type 3 (concrete) T1 T1 Normal procedure h h1 T2 h1 h surfacing 100 mm h2 h1 = 0,6h h2 = 0,4 m h2 h T2 surfacing 100 mm h T1 T2 m C C 0, , h T1 T2 m C C 0,2 3,5 8 0,3 5,0 8 h Simplified procedure h T1 T1 h T1 = 10 C T1 = 10 C Type 2 Concrete deck on steel box, truss or plate girders Temperature changes in industrial structures TM TN C outer face warmer TM inner face warmer (a) Uniform component (b) Stepped component (c) Linear component Concluding remarks Temperature effects may be in some cases significant and shall be considered in structural design. The outer temperatures of a structure depend on absorptivity and orientation of the surface. A uniform temperature component may be derived using national maps of isotherms. For bridges the relationship is given for specification of uniform (effective) temperature component. Two approaches for vertical temperature profile in bridges are given: either linear or non-linear profile should be used. For industrial structures uniform, linear and stepped components are considered; technological temperatures in accordance of design specifications. 4

57 An example: map of minimum temperatures in CR Minimum shade air temperatures of being exceeded by annual extremes with the probability of 0,02. Linear expansion coefficients Tmin = 35,2 C Tmax = 28,1 C mean µt = 31,3 C 28,1 to 30 C 30,1 to 32 C 32,1 to 34 C 34,1 to 36 C Material Aluminium, aluminium alloys Stainless Steel Structural steel Concrete (except as specified below) Concrete with light aggregates Masonry Timber, along grain Timber, across grain Eurocodes: Background and Applications α T ( 10-6 C -1 ) Constituent components of a temperature profile Transient design situations a) a uniform component T u b) a linear component about z-z, T My (in the direction of axis y) c) a linear component about y-y-, T Mz (in the direction of axis z) d) a non-linear component T E Return periods R for the characteristic values Q k Nominal period t t 3 days 3 days < t 3 months 3 months < t 1 year t > 1 year Return period R T max,p = T max {k 1 k 2 ln [ ln (1 p)]} 2 years 5 years 10 years 50 years p = 0,5 p = 0,2 p = 0,1 p = 0,02 T min,p = T min {k 3 + k 4 ln [ ln (1 p)]} The coefficients k 1 to k 4 are given in EN Eurocodes: Background and Applications 28 Reduction coefficients k for different return periods R The characteristic value Q k for return period R Return period R 2 years 5 years 10 years 50 years p 0,5 0,2 0,1 0,02 Q k,r = k Q k,50 T max,r Reduction coefficient k for 0,8 0,86 0, Eurocodes: Background and Applications 1 T min,r 0,45 0,63 0,74 1 s n,r snow 0,64 0,75 0,83 1 v b,r wind 0,77 0,85 0, A uniform temperature component ENV : -24 C, 37 C; in EN , Prague -32 C, 40 C Prestressed concrete bridge ČSN : T N = 55 C T e,min = -20 C T e,max = 35 C ČSN P ENV : T N = 55 C T e,min = -16 C T e,max = 39 C ČSN EN : T N = 66 C T e,min = -24 C T e,max = 42 C Composite bridge ČSN : T N = 65 C T e,min = -25 C T e,max = 40 C ČSN P ENV : T N = 62 C T e,min = -20 C T e,max = 42 C ČSN EN : T N = 73 C T e,min = -28 C T e,max = 45 C 5

58 An example of temperature profile Summer An example of temperature effects- Čekanice, Czech Republic Winter Typical section Eurocodes: Background and Applications 31 EN Load combinations in accordance EN Support section Expr. Main M [MNm] σ hor [MPa] σ dol [MPa] Midspan section M σ hor σ dol [MPa] [MNm] [MPa] 6.10 Q -36,26 1,23-8,89 34,97-6,21 3, T -32,67 0,85-8,27 34,65-6,18 3, a - -27,88 0,34-7,44 27,61-5,44 2, b Q -28,92 0,45-7,62 30,6-5,75 2, Alternative load combinations in accordance with EN CZ 6Q 6T 6a 6bQ 6bT 6.10b T -25,32 0,069-6,99 30,28-5,72 2,73 10 ČSN M [MNm] Support section σ hor [MPa] σ dol [MPa] Mid-span section M [MNm] σ hor [MPa] σ dol [MPa] -32,85 0,32-8,48 32,93-5,83 2, T2E T2N K2E K2N Bending moments at mid-span sections T2 and K2 for linear (E) and non-linear (N) temperatures. Simultaneous temperature components T M, heat (or T M, cool )+ ω N T N,exp (or T M, con ) An example of a fixed member T Nd = 76 1,5 = 114 C q[kn/m] ω M T M, heat (or T M, cool ) + T N, exp (or T N, con ) Coefficients: ω M = 0,75 ω N = 0,35 Concrete: α T = C -1 Linear expansion for α T = C -1 Temperature strain ε T = = 1, Young modulus for concrete member, E MPa Stress σ T = E ε T = 1, = 34 MPa Structural steel: α T = C -1, E MPa - Difference in uniform components of different members ε T = = 1, σ T = E ε T = 1, = 274 MPa - Differences of temperatures of bridge piers Eurocodes: Background and Applications 36 6

59 EN P. Formichi University of Pisa

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61 Brussels, February 2008 Dissemination of information workshop 1 EN : Contents EN 1991 Eurocode 1: Actions on structures Part 1-6 General actions Actions during execution Paolo Formichi Department of Structural Engineering University of Pisa - Italy Brussels, February 2008 Dissemination of information workshop 2 Foreword Section 1 General 1.1 Scope 1.2 Normative references 1.3 Assumptions 1.4 Distinction between principles and application rules 1.5 Terms and definitions 1.6 Symbols Section 2 Classification of Actions Section 3 Design situations and limit states 3.1 General - identification of design situations 3.2 Ultimate limit states 3.3 Serviceability limit states EN : Contents EN : Annexes Brussels, February 2008 Dissemination of information workshop 3 Section 4 Representation of actions 4.1 General 4.2 Actions on structural and non structural members during handling 4.3 Geotechnical Actions 4.4 Actions due to prestresssing 4.5 Predeformations 4.6 Temperature, shrinkage, hydration effects 4.7 Wind Actions 4.8 Snow Loads 4.9 Actions caused by water 4.10 Actions due to atmospheric icing 4.11 Construction loads 4.12 Accidental Actions 4.13 Seismic Actions Brussels, February 2008 Dissemination of information workshop 4 Annex A1 (Normative) Supplementary rules for buildings Annexe A2 (Normative) Supplementary rules for bridges Annexe B (Informative) Actions on structures during alteration, reconstruction or demolition EN : Scope EN : Design Situations and limit states Brussels, February 2008 Dissemination of information workshop 5 EN gives principles and general rules for the determination of actions to be taken into account during the execution of buildings and civil engineering works. It may also be used as guidance for the determination of actions to be taken into account during: - structural alterations - reconstruction - partial or full demolition. Brussels, February 2008 Dissemination of information workshop 6 During execution the following design situations will be taken into account as appropriate: Transient Accidental Seismic It also gives rules for the determination of actions to be used for the design of auxiliary construction works (falsework, scaffolding, propping systems, cofferdam, bracing ), needed for the execution phases. Any selected design situation will be in accordance with the execution process anticipated in the design, and with any revision occurred.

62 Brussels, February 2008 Dissemination of information workshop 7 EN : Design Situations and limit states EN : Design Situations and limit states Any selected transient design situation be associated with a nominal duration equal to, or greater than the anticipated duration of the stage of execution under consideration. Brussels, February 2008 Dissemination of information workshop 8 Nominal duration of the execution phase Return period (years) The design situations should take into account the likelihood for any corresponding return periods of variable actions (e.g. climatic actions). The return periods for the assessment of characteristic values of variable actions during execution may be defined in the National Annex or for the individual project. Recommended return periods of climatic actions are given, depending on the nominal duration of the relevant design situation. A minimum wind velocity during execution may be defined in the National Annex or for the individual project. The recommended basic value for durations of up to 3 months is 20m/s in accordance with EN : Wind Actions. Relationships between characteristic values and return period for climatic actions are given in the appropriate Parts of EN EN : Design Situations and limit states EN : Design Situations and limit states Brussels, February 2008 Dissemination of information workshop 9 Example: Snow loads according to return period [Annex D of EN ] Brussels, February 2008 Dissemination of information workshop 10 Snow loads according to return period [EN ] If the available data show that the annual maximum snow load can be assumed to follow a Gumbel probability distribution, then the relationship between the characteristic value of the snow load on the ground and the snow load on the ground for a mean recurrence interval of n years is given by: s k P n V 6 1 V s = s π n k [ ln( ln(1 P )) + 0,57722] (1 + 2,5923V ) is the characteristic snow load on the ground (with a return period of 50 years) is the annual probability of exceedence (approx. = 1/n) is the coefficient of variation of annual max. snow loads n s n /s k V = V = Return period (years) EN : Ultimate Limit States EN : Ultimate Limit States Brussels, February 2008 Dissemination of information workshop 11 Ultimate limit states need to be verified for all selected transient, accidental and seismic design situations as appropriate during execution in accordance with EN The combinations of actions for accidental design situations can either include the accidental action explicitly or refer to a situation after an accidental event. Brussels, February 2008 Dissemination of information workshop 12 The verifications of the structure should take into account the appropriate geometry and resistance of the partially completed structure corresponding to the selected design situations. Generally, accidental design situations refer to exceptional conditions applicable to the structure or its exposure, such as: impact, local failure and subsequent progressive collapse, fall of structural or non-structural parts, and, in the case of buildings, abnormal concentrations of building equipment and/or building materials, water accumulation on steel roofs, fire, etc. Geometry of the partially completed resisting structure Resistance of the lower floor, which has not necessarily attained its full strength.

63 Brussels, February 2008 Dissemination of information workshop 13 EN : Ultimate Limit States EN : Ultimate Limit States geometry resistance Brussels, February 2008 Dissemination of information workshop 14 Ultimate limit states of STR/GEO - Fundamental combination for transient design situations. Expression (6.10) EN 1990 γ G, jgk, j" + " γ PP" + " γ Q,1Qk,1" + " j 1 i> 1 γ ψ Q Q, i 0, i k, i 1987 Bridgeport Connecticut (US) Inadequate temporary connections + instability of steel members (*) (*) K. Carper Beware of vulnerabilities during construction - Construction and equipment, 3/ Bailey s Crossroad Fairfax (US) Construction of a 26-story building. Concrete was being placed at the 24 th floor and shoring was simultaneously being removed at the 22 nd floor cast two weeks before. Insufficient shear resistance of concrete slabs caused progressive collapse (*) Expressions (6.10a) and (6.10b) EN 1990 j 1 γ G, j j j 1 G G, j k, j " + " γ P" + " k, j P P i 1 γ ψ Q Q, i 0, i ξ γ G " + " γ P" + " γ Q 0,85 ξ 1,00 Q,1 k,1 k, i " + " i> 1 γ ψ Q Q, i 0, i k, i EN : Ultimate Limit States EN : Serviceability Limit States Brussels, February 2008 Dissemination of information workshop 15 Brussels, February 2008 Dissemination of information workshop 16 Accidental design situation Expression (6.11b) EN 1990 Gk, j" + " P" + " Ad " + "( ψ1,1 orψ 2,1) Qk,1" + " j 1 i> 1 Seismic design situation Expression (6.12b) EN 1990 Gk, j" + " P" + " AEd " + " j 1 i> 1 ψ Q 2, i k, i ψ Q 2, i k, i The SLS for the selected design situations during execution needs to be verified, as appropriate, in accordance with EN The criteria associated with the SLS during execution should take into account the requirements for the completed structure. Operations which can cause excessive cracking and/or early deflection during execution and which may adversely affect the durability, fitness for use and/or aesthetic appearance in the final stage has to be avoided. EN : Serviceability Limit States EN : Serviceability Limit States Brussels, February 2008 Dissemination of information workshop 17 Brussels, February 2008 Dissemination of information workshop 18 SLS: : combinations of actions. The combinations of actions should be established in accordance with EN In general, the relevant combinations of actions for transient design situations during execution are: the characteristic combination the quasi-permanent combination Characteristic combination (irreversible SLS) Gk, j" + " P" + " Qk,1" + " j 1 i> 1 ψ Q 0, i k, i Quasi-permanent combination (reversible SLS) Gk, j" + " P" + " j 1 i 1 ψ Q 2, i k, i

64 Brussels, February 2008 Dissemination of information workshop 19 Classification & representation of actions Classification & representation of actions Actions during execution are classified in accordance with EN 1990, and may include: Brussels, February 2008 Dissemination of information workshop 20 those actions that are not construction loads; and construction loads Both types of actions are classified (tables 2.1 and 2.2) depending on: Variation in time (permanent, variable, accidental) Origin (direct, indirect) Spatial variation (fixed, free) Nature (static, dynamic) Construction Loads Classification of Construction Loads Brussels, February 2008 Dissemination of information workshop 21 Construction loads Q c may be represented in the appropriate design situations (see EN 1990), either, as one single variable action, or where appropriate different types of construction loads may be grouped and applied as a single variable action. Single and/or a grouping of construction loads should be considered to act simultaneously with non construction loads as appropriate. Brussels, February 2008 Dissemination of information workshop 22 Construction loads Q c are classified as variable actions Constr. Load Q ca Q cb Q cc Q cd Q ca Q cb Q cc Q cd Q ce Q cf 6 different sources Q ce Q cf Where Construction Loads are classified as fixed, they should be defined tolerances for possible deviation from the theoretical position. Where Construction Loads are classified as free, they should be defined limits of the area where they should be moved or positioned. Representation of Construction Loads Representation of Construction Loads Brussels, February 2008 Dissemination of information workshop 23 Construction loads Q ca Personnel and hand tools Working personnel, staff and visitors, possibly with hand tools or other small site equipment. Modelled as a uniformly distributed load q ca and applied as to obtain the most unfavourable effects. The recommended value is : q ca,k = 1,0 kn/m 2 Brussels, February 2008 Dissemination of information workshop 24 Construction loads Q ca Personnel and hand tools The recommended value has been derived from investigations on construction sites(*), with regard to the following stages of construction: 1. before pouring of concrete slab; 2. after pouring of concrete slab, during the preparation of the next floor. Measurement grid size [m 2 ] 2,32 5,95 9,25 20,90 37,16 Mean Load [kn/m 2 ] 0,31 0,30 0,29 0,30 0,28 10% fractile Load [kn/m 2 ] 0,5% fractile Load [kn/m 2 ] 3,34 2,39 2,68 1,94 1,46 As an example: the 5% fractile value for the 9,25 m 2, is 1,23 kn/m 2 (Gumbel distribution of the random variable is assumed). 1,08 0,92 0,80 0,73 0,72 1% fractile Load [kn/m 2 ] (*) Cast-in-place Concrete in Tall Building Design and Construction Council on Tall Buildings and Urban Habitat Committee 21 D. Mc Graw-Hill Inc Chapter 2: Construction loads. 2,93 2,00 2,18 1,58 1,43

65 Brussels, February 2008 Dissemination of information workshop 25 Representation of Construction Loads Representation of Construction Loads Construction loads Q cb Storage of movable items e.g.: 1. Building and construction materials, precast elements; 2. Equipment. Brussels, February 2008 Dissemination of information workshop 26 Construction loads Q cc Non-permanent equipment in position for use: Static (e.g. formwork panels, scaffolding, falsework, machinery, containers) During movement (e.g. travelling forms launching griders and nose, counterweights) Modelled as a free action and represented by a UDL q cb and a concentrated load F cb For bridges, the following values are recommended minimum values: q cb,k = 0,2 kn/m 2 F cb,k = 100 kn Unless more accurate information is available, they may be modelled by a uniformly distributed load with a recommended minimum characteristic value of q cc,k = 0,5 kn/m 2 Representation of Construction Loads Representation of Construction Loads Brussels, February 2008 Dissemination of information workshop 27 Construction loads Q cd Movable heavy machinery and equipment usually wheeled or tracked e.g.: Cranes, lifts, vehicles, lift trucks, power installations, jacks, heavy lifting devices. Brussels, February 2008 Dissemination of information workshop 28 Construction loads Q ce Accumulation of waste materials e.g.: surplus construction materials excavated soil or demolition materials. When not defined in the project specification, information for the determination of actions may be found in: - EN for actions due to vehicles - EN for actions due to cranes. These loads are taken into account by considering possible mass effects on horizontal, inclined and vertical elements (such as walls). These loads may vary significantly, and over short time periods, depending on types of materials, climatic conditions, build-up and clearance rates. Representation of Construction Loads Representation of Construction Loads Brussels, February 2008 Dissemination of information workshop 29 Construction loads Q cf Loads from part of structure in a temporary state before the final design actions take effect e.g. loads from lifting operations. Taken into account and modelled according to the planned execution sequences, including the consequences of those sequences (e.g. loads and reverse load effects due to particular processes of construction, such as assemblage). Brussels, February 2008 Dissemination of information workshop 30 Construction loads during the casting of concrete (4.11.2) Actions to be taken into account simultaneously during the casting of concrete may include: - working personnel with small site equipment (Q ca ); - formwork and loadbearing members (Q cc ); - the weight of fresh concrete (which is one example of Q cf ), as appropriate.

66 Brussels, February 2008 Dissemination of information workshop 31 Representation of Construction Loads EN : Accidental Actions Q ca, Q cc and Q cf may be given in the National Annex. Recommended values for fresh concrete (Q cf ) may be taken from Table 4.2 and EN , Table A.1. Other values may have to be defined, for example, when using self-levelling concrete or pre-cast products. Brussels, February 2008 Dissemination of information workshop 32 Accidental actions such as impact from construction vehicles, cranes, building equipment or materials in transit (e.g. skip of fresh concrete), and/or local failure of final or temporary supports, including dynamic effects, that may result in collapse of load-bearing structural members, shall be taken into account, where relevant. Abnormal concentrations of building equipment and/or building materials on load-bearing structural members should also be taken into account Dynamic effects may be defined in the National Annex or for the individual project. The recommended value of the dynamic amplification factor is 2. In specific cases a dynamic analysis is needed. EN : Seismic Actions EN : Annex A1 (normative) Brussels, February 2008 Dissemination of information workshop 33 Seismic actions should be determined according to EN 1998, taking into account the reference period of the considered transient situation. The design values of ground acceleration and the importance factor γ I may be defined in the National Annex or for the individual project. Brussels, February 2008 Dissemination of information workshop 34 Supplementary rules for buildings Representative values of the variable action due to construction loads may be set by the National Annex, within a recommended range of ψ 0 = 0,6 to 1,0. The recommended value of ψ 0 is 1,0. The minimum recommended value of ψ 2 is 0,2 and it is further recommended that values below 0,2 are not selected For the verification of serviceability limit states, the combinations of actions to be taken into account should be the characteristic and the quasi-permanent combinations. EN : Annex A2 (normative) EN : Annex A2 (normative) Brussels, February 2008 Dissemination of information workshop 35 Supplementary rules for bridges For the incremental launching of bridges the design values for vertical deflections may be found in the National Annex. The recommended values are: a) ± 10 mm longitudinally for one bearing, the other bearings being assumed to be at the theoretical level; b) ± 2,5 mm in the transverse direction for one bearing, the other bearings being assumed to be at the theoretical level. Brussels, February 2008 Dissemination of information workshop 36 Supplementary rules for bridges Construction Loads For the incremental launching of bridges horizontal forces due to friction effects should be determined, and applied between the bridge structure, the bearings and the supporting structures, with dynamic action effects taken into account where appropriate. It is recommended that the design value of the total horizontal friction forces should be not less than 10 % of the vertical loads, and should be determined to give the least favourable effects. The horizontal friction forces at every pier should be determined with the appropriate friction coefficients, µ min and µ max (defined in the National Annex). Unless more accurate values are available from tests for movements on very low friction surfaces (e.g. PTFE) the recommended values are : µ min = 0 µ max = 0,04

67 Brussels, February 2008 Dissemination of information workshop 37 EN : Annex B (informative) Actions on structures during alteration, reconstruction or demolition Brussels, February 2008 Dissemination of information workshop 38 Thank you for your attention The actual performance of structures affected by deterioration should be taken into account in the verification of the stages for reconstruction or demolition. The investigation of structural conditions to enable the identification of the load-bearing capacity of the structure and to prevent unpredictable behaviour during reconstruction or demolition should be undertaken. The reliability for the remaining structure or parts of the structure under reconstruction, partial or full demolition should be consistent with that considered in the Eurocodes for completed structures or parts of structures.

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69 EN A. Vrouwenvelder TNO

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71 Brussels, February 2008 Dissemination of information workshop 1 Brussels, February 2008 Dissemination of information workshop 2 EN Eurocode 1 Accidental Actions Ton Vrouwenvelder TNO Bouw / TU Delft EN 1990 Section 2.1 Basic Requirements (4)P A structure shall be designed and executed in such a way that it will not be damaged by events like -explosion - impact and - consequences of human errors to an extent disproportionate to the original cause Note: Further information is given in EN Brussels, February 2008 Dissemination of information workshop 3 Brussels, February 2008 Dissemination of information workshop 4 EN 1990 guidance: reducing hazards low sensitive structural form survival of local damage sufficient warning at collapse tying members Brussels, February 2008 Dissemination of information workshop 5 Brussels, February 2008 Dissemination of information workshop 6 Eurocode EN General 2. Classification 3. Design situations 4. Impact 5. Explosions World Trade Center USA, 2001 Annexes A. Design for localised failure B. Risk analysis C. Dynamics D. Explosions

72 Brussels, February 2008 Dissemination of information workshop 7 4. Impact 3 Design strategies Brussels, February 2008 Dissemination of information workshop 8 Type of road Vehicle type F d,x [kn] Motorway Country roads Urban area Parking place Parking place Truck Truck Truck Truck Passenger car Annex C: force model Brussels, February 2008 Dissemination of information workshop 9 Brussels, February 2008 Dissemination of information workshop 10 Annex B: scenario model 2500 F[kN] upper lower theorie E [knm] F=v (km) model en experiment Brussels, February 2008 Dissemination of information workshop 11 Table 4.2.1: Data for probabilistic collision force calculation variable designation type mean stand dev n number of lorries/day deterministic T reference time deterministic 100 years - λ accident rate deterministic m -1 - b width of a vehicle deterministic 2.50 m - α angle of collision course rayleigh 10 o 10 o v vehicle velocity lognormal 80 km/hr 10 km/hr a deceleration lognormal 4 m 2 /s 1.3 m/s 2 m vehicle mass normal 20 ton 12 ton k vehicle stiffness deterministic 300 kn/m - Brussels, February 2008 Dissemination of information workshop force [kn] eq distance [m] Life time exceedence probability: 10-3

73 Brussels, February 2008 Dissemination of information workshop 13 Design example: bridge column in motorway x Brussels, February 2008 Dissemination of information workshop 14 Bending moment: F dy H h y M dx = a( H a ) H 1.25 ( ) F dx = 1000 = 940 knm 5.00 a b b width 0.50 m h thickness 1.00 m H column height 5 m f y yield stress steel 300 MPa f c concrete strength 50 MPa ρ reinforcement ratio 0.01 Resistance: M Rdx = 0.8 ω h 2 b f y = = 1200 knm > 940 knm Brussels, February 2008 Dissemination of information workshop 15 Brussels, February 2008 Dissemination of information workshop Annex D: gas explosions in buildings gas explosions in tunnels dust explosions INTERNAL NATURAL GAS EXPLOSIONS The design pressure is the maximum of: p d = 3 + p v p d = p v +0,04/(A v /V) 2 p d = nominal equivalent static pressure [kn/m 2 ] A v = area of venting components [m 2 ] V = volume of room [m 3 ] Validity: V < 1000 m 3 ; 0,05 m -1 < A v / V < 0,15 m -1 Annex B: load duration = 0.2 s Design Example: Compartment in a multi story building Brussels, February 2008 Dissemination of information workshop 17 Brussels, February 2008 Dissemination of information workshop 18 explosion pressure: H = 3m p d B = 8 m p Ed =3+ p v /2 + 0,04/(A v /V) 2 = / = 6.5 kn/m 2 self weight = 3.0 kn/m 2 live load = 2.0 kn/m 2 Design load combination (bottom floor): Compartment: 3 x 8 x 14 m Two glass walls (p v =3 kn/m 2 ) and two concrete walls p da = p SW + p E + ψ 1LL p LL = *2.00 = kn/m 2

74 Brussels, February 2008 Dissemination of information workshop 19 Dynamic increase in load carrying capacity ϕ d = 1 + p p SW Rd 2 u max g ( Δ t ) Δt = 0.2 s = load duration g = 10 m/s 2 u max = 0.20 m = midspan deflection at collapse p sw = 3,0 kn/m 2 and p Rd =7.7 kn/m 2 2 Brussels, February 2008 Dissemination of information workshop 20 Be careful for upper floors and columns P sw ϕ d = [ * (0.2 ) ] = 1.6 p REd = ϕ d p Rd = 1.6 * 7.7 = 12.5 kn/m 2 > 10.5 kn/m2 edge column p E B centre column Conclusion: bottom floor system okay Brussels, February 2008 Dissemination of information workshop 21 BLEVE in een overkluizing Brussels, February 2008 Dissemination of information workshop 22 Y X Y Z X Brussels, February 2008 Dissemination of information workshop 23 Brussels, February 2008 Dissemination of information workshop 24 Annex A: Classification of buildings Consequences class Example structures class 1 low rise buildings where only few people are present class 2, lower group most buildings up to 4 stories Z Y X.1E-1.9E-2.8E-2.7E-2.6E-2.5E-2.4E-2.3E-2.2E-2.1E-2 0 class 2, upper group class 3 most buildings up to 15 stories high rise building, grand stands etc.

75 Brussels, February 2008 Dissemination of information workshop 25 Brussels, February 2008 Dissemination of information workshop 26 Annex A: What to do s = 4 m Class 2a (lower group) s = 4 m Class 1 No special considerations interne trekbandt i Class 2, Lower Group Horizontal ties in floors Frames Class 2, Lower group Full cellular shapes Wall structures Floor to wall anchoring. Class 2, Upper Group Horizontal ties and effective vertical ties OR limited damage on notional removal OR special design of key elements Class 3 Risk analysis and/or advanced mechanical analysis recommended L = 5 m alle liggers kunnen worden ontworpen om als trekband te dienen omtrek trekband T p interne trekband T i randkolom Class 2a (lower group) Background horizontal typings Brussels, February 2008 Dissemination of information workshop 27 Brussels, February 2008 Dissemination of information workshop 28 L = 5 m s = 4 m s = 4 m interne trekband 2Ø12 omtrek trekband 2Ø12 s s total load on center column R = (g k + ψ q k ) L s = p L s L L interne trekband 2Ø12 T i = 0,8 s L p T i randkolom T i T i T i = 0.8 (g k +Ψ q k )sl = 0.8{3+0.5*3}x4x5=88 kn>75 kn FeB 500: A = 202 mm 2 or 2 Ø12mm middenkolom Background typing forces Brussels, February 2008 Dissemination of information workshop 29 T i = 0.75 p s L Equilibirum for δ = (s+l)/6 Brussels, February 2008 Dissemination of information workshop 30 Suggestion: drukkrachten trekkrachten R design corner column as a key element. verplaatsing δ δ X R X T i

76 Brussels, February 2008 Dissemination of information workshop 31 Example structure, Class 2, Upper Group, Framed L =7.2 m, s =6 m, q k =g k =4 kn/m 2, Ψ=1.0 internal ties perimeter tie Brussels, February 2008 Dissemination of information workshop 32 Example structure Internal horizontal tie force T i = 0.8 (g k + Ψ q k ) s L = 0.8 {4+4} (6 x 7.2) = 276 kn FeB 500: A = 550 mm 2 or 2 ø18 mm. Vertical tying force: L s T i = (g k + Ψ q k ) s L = {4+4} (6 x 7.2) = 350 kn FeB 500: A = 700 mm 2 or 3 ø18 mm. Class 2 higher class walls Brussels, February 2008 Dissemination of information workshop 33 Brussels, February 2008 Dissemination of information workshop 34 Class 2 higher class walls Tyings 1,2 m z interne trekband T i omtrek trekband T p interne trekband T i Horizontal: T i = F t (g k + ψq k ) /7,5 z/5 kn/m > F t Periphery: T p = F t Vertical: T = 34 A / 8000 (H/t)² in N > 100 kn/m F t = n s kn/m < 60 kn/m n s = number of storeys z = span A = horizontal cross section of wall [mm²] H = free storey height t = wall thickness dragende wand Class 2 higher class walls Brussels, February 2008 Dissemination of information workshop 35 Brussels, February 2008 Dissemination of information workshop 36 Design Example: Effect of tyings in walls L = 7,2 m, H = 2,8 m en t = 250 mm T = /8000 (2800/250)² = = ³ N = 960 kn > 720 kn maximal distance 5 m maximal distance from edge: 2.5 m Result: 2 tyings of 480 kn

77 Brussels, February 2008 Dissemination of information workshop 37 class 3: Risk analysis Brussels, February 2008 Dissemination of information workshop 38 Effect of vertical tyings gaping Guidance can be found in Annex B: Definition of scope and limitations Qualitative Risk analysis hazard identification hazard scenarios description of consequences definition of measures Reconsideration of scope and assumptions Quantitative Risk Analyisis inventory of uncertainties modelling of uncertatinties probabilistic calculations quantification of consequences calculation of risks Risk management risk acceptance criteria decision on measures Presentation Brussels, February 2008 Dissemination of information workshop 39 Brussels, February 2008 Dissemination of information workshop 40 Risk Analysis Eastern Scheldt Storm Surge Barrier (1980) Office building Zwolle (The Netherlands) London Eye Brussels, February 2008 Dissemination of information workshop 41 hazards Brussels, February 2008 Dissemination of information workshop 42 Points of attention in risk analysis list of hazards irregular structural shapes new construction types or materials number of potential casualties strategic role (lifelines) Earthquake Landslide Tornado Avalanche Rock fall High groundwater Flood Volcano eruption Internal explosion External explosion Internal fire External fire Impact by vehicle etc Mining subsidence Environmental attack Vandalism Demonstrations Terrorist attack Design error Material error Construction error User error Lack of maintenance

78 Brussels, February 2008 Dissemination of information workshop 43 Step 1 Step 2 Step 3 Identifical and modelling Assessment of damage Assessment of the of relevant accidental states to structure from performance of the hazards different hazards damaged structure Brussels, February 2008 Dissemination of information workshop 44 Risk calculation: Step 1: identification of hazard H i Step 2: damage D j at given hazard Step 3: structural behavour S k and cpmsequences C(S k ) Risk = p( H i ) p( D j H i ) p( S k D j )C( S k ) Assessment of the probability of occurence of different hazards with different intensities Assessment of the probability of different states of damage and corresponding consequences for given hazards Assessment of the probability of inadequate performance(s) of the damaged structure together with the corresponding consequence(s) Take sum over all hazards and damage types Conclusions Brussels, February 2008 Dissemination of information workshop 45 Brussels, February 2008 Dissemination of information workshop 46 EN : valuable document, but not a masterpiece of European harmonisation Reasons: large prior differences member state autonomy in safety matters legal status different in every country Relevant Background Documents ISO-documents COST actions C28 and TU0601 Background document for the ENV-version of EC1 Part 2-7 (TNO, The Netherlands, 1999) Leonardo da Vinci Project CZ/02/B/F/PP Handbooks Implementtion of Eurocodes (2005) It will be interesting to see the National Annexes and NDP s.

79 EN J.-A. Calgaro CGPC, CEN/TC250 Chairman M. Tschumi SBB-CFF-FFS

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81 Brussels, February 2008 Dissemination of information workshop 1 EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 2 FOREWORD Traffic Loads on Road Bridges and Footbridges SECTION 1 SECTION 2 SECTION 3 SECTION 4 SECTION 5 SECTION 6 ANNEX A (INFORMATIVE) ANNEX B (INFORMATIVE) GENERAL CLASSIFICATION OF ACTIONS DESIGN SITUATIONS ROAD TRAFFIC ACTIONS AND OTHER ACTIONS SPECIFICALLY FOR ROAD BRIDGES ACTIONS ON FOOTWAYS, CYCLE TRACKS AND FOOTBRIDGES RAIL TRAFFIC ACTIONS AND OTHER ACTIONS SPECIFICALLY FOR RAILWAY BRIDGES MODELS OF SPECIAL VEHICLES FOR ROAD BRIDGES FATIGUE LIFE ASSESSMENT FOR ROAD BRIDGES ASSESSMENT METHOD BASED ON RECORDED TRAFFIC Jean-Armand Calgaro Chairman of CEN/TC250 EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 3 GENERAL ORGANISATION FOR ROAD BRIDGES Traffic load models - Vertical forces : LM1, LM2, LM3, LM4 - Horizontal forces : braking and acceleration, centrifugal,, transverse Groups of loads - gr1a, gr1b, gr2, gr3, gr4, gr5 - characteristic, frequent and quasi-permanent values Combination with actions other than traffic actions Brussels, February 2008 Dissemination of information workshop 4 LOAD MODELS FOR LIMIT STATES OTHER THAN FATIGUE LIMIT STATES Field of application : loaded lengths less than 200 m (maximum length taken into account for the calibration of the Eurocode For very long loaded lengths, see National Annex) Load Model Nr.. 1 Concentrated and distributed loads (main model general and local verifications) Load Model Nr.. 2 Single axle load (semi-local and local verifications) Load Model Nr.. 3 Set of special vehicles (general and local verifications) Load Model Nr.. 4 Crowd loading : 5 kn/m 2 (general verifications) EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 5 Traffic Load Models Road bridges LM1 (4.3.2) LM2 (4.3.3) LM3 (4.3.4) LM4 (4.3.5) Characteristic values Frequent values Quasi-permanent values 1000 year return period (or probability of exceedance of 5% in 50 years) for traffic on the main roads in Europe (α factors equal to 1, see 4.3.2). 1 week return period for traffic on the main roads in Europe (α factors equal to 1, see 4.3.2) year return period 1 week return period for (or probability of traffic on the main roads exceedance of 5% in 50 in Europe (β factor equal years) for traffic on the to 1, see 4.3.3). main roads in Europe (β factor equal to 1, see 4.3.3). Set of nominal values. Not relevant Basic values defined in annex A are derived from a synthesis based on various national regulations. Nominal value deemed to Not relevant represent the effects of a crowd. Defined with reference to existing national standards. Calibration in accordance with definition given in EN Not relevant Not relevant Not relevant Brussels, February 2008 Dissemination of information workshop 6 Carriageway width w width measured between kerbs (height more than 100 mm recommended value) or between the inner limits of vehicle restraint systems

82 Brussels, February 2008 Dissemination of information workshop 7 EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Division of the carriageway into notional lanes Carriageway width w Number of notional lanes Width of a notional lane w l Width of the remaining area w < 5, 4 m n = 1 3 m w 3m 5,4m w < 6m n = 2 l l w 6 m w n l = Int 3 m w 3 nl 3 w NOTE For example, for a carriageway width equal to 11m, 3 3 n = Int = l, and the width of the remaining area is = 2m. w 2 1 Lane Nr.. 1 (3m) 2 Lane Nr.. 2 (3m) 3 Lane Nr.. 3 (3m) 4 Remaining area 0 Brussels, February 2008 Dissemination of information workshop 8 The main load model (LM1) q rk = 2,5 kn/m 2 q 1k 1k = 9 kn/m 2 q 2k = 2,5 kn/m 2 q 3k = 2,5 kn/m 2 q rk = 2,5 kn/m 2 EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 9 The main load model for road bridges (LM1) : diagrammatic representation For the determination of general effects, the tandems travel centrally along the axes of notional lanes Brussels, February 2008 Dissemination of information workshop 10 The main load model (LM1) Example of values for α factors (National Annexes) 1 st class : international heavy vehicle traffic 2 nd class : «normal» heavy vehicle traffic For local verifications,, a tandem system should be applied at the most unfavourable location. Where two tandems on adjacent notional lanes are taken into account, they may be brought closer, the distance between axles being not less than 0,50 m Classes α Q 1 α Qi i 2 α q1 α qi i 2 α qr 1 st class nd class 0,9 0,8 0,7 1 1 EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 11 Brussels, February 2008 Dissemination of information workshop 12 Examples of influence surfaces (transverse bending moment) for a deck slab Example of application of LM1 to the concrete slab of a composite bridge

83 Brussels, February 2008 Dissemination of information workshop 13 EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Load model Nr.. 2 (LM2) Brussels, February 2008 Dissemination of information workshop 14 Dispersal of concentrated loads a) Pavement and concrete slab b) Pavement and orthotropic deck 1 Wheel contact pressure 1 Wheel contact pressure 2 Pavement 2 Pavement 3 Concrete slab 3 Bridge floor Recommended value : β Q = α Q1 (National Annex) 4 Middle surface of concrete slab 4 Middle surface of the bridge floor 5 Transverse member EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 15 HORIZONTAL FORCES : Braking and acceleration (Lane Nr.. 1 ) Brussels, February 2008 Dissemination of information workshop 16 HORIZONTAL FORCES : Centrifugal forces Qk = 0,6α Q1(2Q1k ) + 0, 10α q1q1k w1l 180α Q1kN Q k 900 kn α Q1 Q1 = α q1 = 1 Q lk = ,7L For 0 L 1,2 m Q lk = ,7L For L > 1,2 m Q 2 = 0, (kn) if r < 200 m tk Q v Q = 40Q r (kn) if 200 r 1500 m tk v / Q = 0 if r > 1500 m tk r : horizontal radius of curvature centreline [m] of the carriageway Q v : total maximum weight of vertical concentrated loads of the tandem systems of LM1 αqi (2Q ik ) i EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 17 Group of loads gr1a : LM1 + «reduced» value of pedestrian load on footways or cycle tracks (3 kn/m 2 ) Groups of loads Brussels, February 2008 Dissemination of information workshop 18 Group of loads gr3 : loads on footways and cycle tracks Group of loads gr4 : crowd loading Group of loads gr1b : LM2 (single axle load) Group of loads gr2 : characteristic values of horizontal forces, frequent values of LM1 Group of loads gr5 : special vehicles (+ special conditions for normal traffic)

84 Brussels, February 2008 Dissemination of information workshop 19 EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Table 4.4b Assessment of groups of traffic loads (frequent values of the multi-component action) Load type Reference EN Load system CARRIAGEWAY Vertical forces FOOTWAYS AND CYCLE TRACKS (1) LM1 (TS and UDL systems) Frequent values LM2 (single axle) Uniformly distributed load gr1a Groups of loads gr1b Frequent values gr3 Frequent value a) a) See (3). One footway only should be considered to be loaded if the effect is more unfavourable than the effect of two loaded footways. Brussels, February 2008 Dissemination of information workshop 20 FATIGUE LOAD MODELS Load Model Nr.. 1 (FLM1) : Similar to characteristic Load Model Nr.. 1 0,7 x Q ik - 0,3 x q ik - 0,3 x q rk Load Model Nr.. 2 (FLM2) : Set of «fequent» lorries Load Model Nr.. 3 (FLM3) : Single vehicle Load Model Nr.. 4 (FLM4) : Set of «equivalent» lorries Load Model Nr.. 5 (FLM5) : Recorded traffic EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 21 Table Indicative number of heavy vehicles expected per year and per slow lane (FLM3 and FLM4 Models) Traffic categories 1 Roads and motorways with 2 or more lanes per direction with high flow rates of lorries 2 Roads and motorways with medium flow rates of lorries 3 Main roads with low flow rates of lorries 4 Local roads with low flow rates of lorries N obs per year and per slow lane 2, , , , Brussels, February 2008 Dissemination of information workshop Axle spacing Frequent (m) axle loads LORRY SILHOUETTE (kn) 4, ,20 1,30 3,20 5,20 1,30 1,30 3,40 6,00 1,80 4,80 3,60 4,40 1, Wheel type (see Table 4.8) A B A B B A B C C C A B B B A B C C C FLM2 Set of «frequent» lorries EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 23 FLM2 : Definition of wheels and axles (Table 4.8) AXLE/WHEEL TYPES GEOMETRICAL DEFINITION Brussels, February 2008 Dissemination of information workshop 24 Fatigue Load Model Nr.3 (FLM3) A B C A second vehicle may be taken into account : Recommended axle load value Q = 36 kn Minimum distance between vehicles : 40 m

85 Brussels, February 2008 Dissemination of information workshop 25 EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 26 Verification procedure with Load Model FLM 3 Determination of the maximum and minimum stresses resulting from the transit of the model along the bridge Δσ LM = Maxσ LM Minσ LM The stress variation is multiplied by a local dynamic amplification factor in the vicinity of expansion joints Δϕ fat The model is normally centered in every slow lane defined in the project specification.. But where the transverse position is important, a statistical distribution of this position should be taken into account. Finally : Δσ fat = λδϕ fatδσ LM Frequency distribution of transverse location of a vehicle (Models 3 to 5) EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 27 Fatigue Load Models for road bridges Representation of the additional amplification factor Brussels, February 2008 Dissemination of information workshop 28 Principle of the fatigue verification with FLM 3 Δϕfat : Additional amplification factor D : Distance of the cross-section under consideration from the expansion joint EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 29 Brussels, February 2008 Dissemination of information workshop 30 VEHICLE TYPE TRAFFIC TYPE LORRY Axle spacing (m) Equivalent axle loads (kn) 4, Long distance Lorry persentage Medium distance Lorry percentage Local traffic Lorry percentage Wheel type 20,0 40,0 80,0 A B FLM4 Set of «equivalent» lorries. 4,20 1,30 3,20 5,20 1,30 1,30 3,40 6,00 1,80 4,80 3,60 4,40 1, ,0 10,0 5,0 A B B 50,0 30,0 5,0 A B C C C 15,0 15,0 5,0 A B B B 10,0 5,0 5,0 A B C C C

86 Brussels, February 2008 Dissemination of information workshop 31 EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 32 ACTIONS FROM VEHICLES ON THE BRIDGE Vehicles on footways and cycle tracks Impact forces on kerbs Impact forces on safety barriers EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 33 Brussels, February 2008 Dissemination of information workshop 34 LOAD MODELS FOR FOOTWAYS AND FOOTBRIDGES (Section 5) LOAD MODEL Nr.1 Uniformly distributed load q fk LOAD MODEL Nr.2 Concentrated load Q fwk (10 kn recommended) LOAD MODEL Nr.3 Service vehicle Q serv EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 35 Brussels, February 2008 Dissemination of information workshop 36 q Recommended characteristic value for : - footways and cycle tracks on road bridges, - short or medium span length footbridges : Recommended expression for long span length footbridges : fk q fk = 2,0 + 2,5 kn/m 120 L q q fk fk = 5,0 kn/m kn/m 2 5,0 kn/m 2 2 For footbridges only, a horizontal force should be taken into account, to be applied along the deck axis at the surfacing level Q flk. Its characteristic value, which may be altered in the National Annex, is equal to the higher of the two following values : 10% of the total uniformly distributed load as defined in ,.1, 60% of the total service vehicle load where relevant ( (1)P). The horizontal force is applied simultaneously with the vertical load, but not with the concentrated load. L is the loaded length [m]

87 Brussels, February 2008 Dissemination of information workshop 37 EN «Traffic Loads on Bridges» EN «Traffic Loads on Bridges» Brussels, February 2008 Dissemination of information workshop 38 Groups of loads for footbridges Group of loads gr1 Thank you for your attention Group of loads gr2

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89 RAILWAY ACTIONS M.T. Brussels, February 2008 Dissemination of information workshop 1 EN CONTENTS Brussels, February 2008 Dissemination of information workshop 2 Actions on structures Traffic loads on bridges RAILWAY ACTIONS. SELECTED CHAPTERS FROM EN AND ANNEX A2 OF EN 1990 Dr. h. c. Marcel Tschumi Foreword Section 1 Section 2 Section 3 Section 4 Section 5 Section 6 General Classification of actions Design situations Road traffic actions and other actions specifically for road bridges Actions on footways,, cycle tracks and footbridges Rail traffic actions and other actions specifically for railway bridges EN CONTENTS (continued( continued) Brussels, February 2008 Dissemination of information workshop 3 EN Annex A2 - CONTENT Brussels, February 2008 Dissemination of information workshop 4 Actions on structures Traffic loads on bridges Annex A (I) Annex B (I) Annex C (N) Annex D (N) Annex E (I) Annex F (I) Annex G (I) Annex H (I) Models of special vehicles for road bridges Fatigue life assessment for road bridges. Assessment method based on recorded traffic Dynamic factors 1+ϕ for real trains Basis for the fatigue assessment of railway structures Limits of validity of load model HSLM and the selection of the critical universal train from HSLM-A Criteria to be satisfied if a dynamic analysis is not required Method for determining the combined response of a structure and track to variable actions Load models for rail traffic loads in transient situations Basis of structural design Application for bridges Section A2.1 Field of application Section A2.2 Combinations of actions A2.2.1 General A2.2.2 for road bridges A2.2.3 for footbridges A2.2.4 for railway bridges A2.2.5 Section A2.3 Ultimate limit states Section A2.4 Serviceability limit states A2.4.1General A2.4.2 serviceability criteria for road bridges A2.4.3 serviceability criteria for footbridges A2.4.4 serviceability criteria for railway bridges Notations and dimensions specifically for railways Load Model 71 Brussels, February 2008 Dissemination of information workshop 5 Brussels, February 2008 Dissemination of information workshop 6 S : gauge U : cant Q s : noising force (1) Running surface (2) Longitudinal forces acting along the centreline of the track The characteristic values given in this figure shall be multiplied by a factor α on lines carrying rail traffic which is heavier or lighter than normal rail traffic. When multiplied by the factor α, the loads are called "classified vertical loads". This factor α shall be one of the following: : 0,75-0,83-0,91-1,00-1,10-1,21-1,33 1,46. The value 1,33 is normally recommended on lines for freight traffic and international lines (UIC CODE 702, 2003). The actions listed below shall be multiplied by the same factor α : centrifugal forces nosing force traction and braking forces load model SW/0 for continuous span bridges 1

90 Relation between LM 71 and the 6 real service trains in UIC Code LM SW/0 et LM SW/2 (heavy( traffic) Brussels, February 2008 Dissemination of information workshop 7 Brussels, February 2008 Dissemination of information workshop 8 2 of 6 examples of real service trains Load model SW/0 SW/2 qvk [kn/m] a [m] 15,0 25,0 c [m] 5,3 7,0 (1+ϕ) S real trains 1-6 Φ S LM71 Example of a heavy weight waggon Equivalent vertical loading for earthworks Brussels, February 2008 Dissemination of information workshop 9 Brussels, February 2008 Dissemination of information workshop 10 α x LM71 (and SW/2 where required), without dynamic factor, uniformly distributed over a width of 3,00 m at a level 0,70 m below the running surface of the rail. Wagon DB with 32 axles, selfweight 246 t, cantilevers included, pay load 457 t, mass per axle 22 t, l tot = 63,3 m Principal factors influencing dynamic behaviour Brussels, February 2008 Dissemination of information workshop 11 Dynamic factors according to the quality of track maintenance Brussels, February 2008 Dissemination of information workshop 12 the speed of traffic across the bridge, the span L of the element, the mass of the structure, the natural frequencies of the whole structure and relevant elements of the structure, the number of axles, axle loads and the spacing of axles, the damping of the structure, vertical irregularities in the track, the unsprung/sprung mass and suspension characteristics of the vehicle, the presence of regularly spaced supports of the deck slab (cross girders), vehicle imperfections (wheel flats, out of round wheels, etc.), the dynamic characteristics of the track (ballast, sleepers, track components etc.). Dynamic factors ( ) for static calculations: Φ 2 for carefully maintained track Φ 3 for standard track (means:poor track) The dynamic factor Φ, which enhances the static load effects under Load Models LM 71, LM SW/0 and LM SW/2, is taken as either Φ2 2 or Φ3, according to the quality of track maintenance. The dynamic factors Φ2 2 et Φ3 3 are calculated on the basis of formulae based on a value called determinant length LΦ given in Table 6.2 of the Eurocode.. If no dynamic factor is specified Φ3 shall be used. 2

91 The four existing different dynamic factors and enhancements written for carefully maintained track Brussels, February 2008 Dissemination of information workshop 13 Vision of future European Network Brussels, February 2008 Dissemination of information workshop 14 Dynamic enhancement for real trains 1 + ϕ = 1 + ϕ' + (½) ϕ'' Dynamic enhancement for fatigue calculations ϕ = 1 + ½(ϕ' + (½)ϕ'') Dynamic factor Φ 2 (Φ 3 ) for static calculations (determinant lengths L Φ due to table 6.2) Dynamic enhancement for dynamic studies ϕ' max y / y 1 dyn = dyn stat The freedom for the choice of the factor α could provoke a non homogeneous railway network in Europe! Therefore in UIC Leaflet 702 (2003) α = 1,33 is generally recommended for all new bridges constructed for the international freight network, unfortunately not obligatory! Year 2002 Year 2100 α=1,33 Choice of the factor α Choice of the factor α Brussels, February 2008 Dissemination of information workshop 15 Brussels, February 2008 Dissemination of information workshop 16 ULS: For new bridges it should absolutely be adopted α = 1,33. Fatigue: All calculations are done with the Load Model 71 and the factor α = 1,00. Existing bridges The question of updated rail traffic actions is currently studied within the European Research Project «Sustainable Bridges - Assessment for Future Traffic Demands and longer Lives». See: Choice of the factor α Choice of the factor α Brussels, February 2008 Dissemination of information workshop 17 Brussels, February 2008 Dissemination of information workshop 18 Serviceability Limit States (SLS) Interaction track bridge: Theoretically this is a Seviceability Limit State (SLS) for the bridge and an Ultimate Limit State (ULS ) for the rail. But as the given permissible rail stresses and deformations were obtained by deterministic design methods, calibrated on the existing practice, the calculations for interaction have to be done in contradiction to EN1991-2, where there is a mistake - always with α = 1,00!! Serviceability Limit States (SLS) Permissible vertical deflections: To check the permissible vertical deflection with a severe formula given later for speeds less than 200 km/h, to minimise track maintenance and to avoid dynamic studies (note: more stiffness costs nothing when doing calculations with LCC), α = 1,00 shall be adopted, even if α = 1,33 is taken into consideration for ULS. 3

92 Classification of international lines Heavier loads do not significantly influence the costs of bridges! Brussels, February 2008 Dissemination of information workshop 19 Brussels, February 2008 Dissemination of information workshop 20 Due to UIC CODE 700 Mass per axle A B C D E Increase of costs in % due to α = 1,33, related to those calculated with α = 1,0 / bridges built with traffic interference (ERRI D 192/RP 4, 1996): Mass per m = p 1 5 t/m 16t A 18t B1 20t 22,5t 25t ,4 t/m 7,2 t/m 8 t/m 8,8 t/m B2 C2 C3 C4 D2 D3 D4 E4 E Worblaufen Muota Mengbach Ness Buchloe Kempten Heavier loads do not significantly influence the costs of bridges! Interaction track - bridge Brussels, February 2008 Dissemination of information workshop 21 Brussels, February 2008 Dissemination of information workshop 22 Increase of costs in % due to α = 1,33, related to those calculated with α = 1,0 / bridges built without traffic interference, (ERRI D 192/RP 4, 1996): 6 Relative displacements of the track and of the bridge, caused by the combination of the effects of thermal variations, train braking and traction forces, as well as deflection of the deck under vertical traffic loads (LM 71),, lead to the track/bridge phenomenon that results in additional stresses to the bridge and the track. Take LM 71 with α = 1.00 (even( if α > 1.00 for ULS)! La Sormonne Sallaumines Mollebakken Kambobekken RN2/TGVNord Verberie Scarpe Holendalen Vlake Limitation of additional permissible stresses in the rail Examples of expansion lengths Brussels, February 2008 Dissemination of information workshop 23 Brussels, February 2008 Dissemination of information workshop 24 Practice with rail UIC 60, steel grade giving at least 900 N/mm2 strength, minimum curve radius r 1500 m, laid on ballasted track with concrete sleepers and consolidated, > 30 cm deep ballast, the permissible additional stresses in continuous welded rail on the bridge due to interaction is: compression: traction: 72 N/mm2 92 N/mm2 4

93 Avoid where ever possible expansion lengths near the bridge! Fatigue: choice for α and λ Brussels, February 2008 Dissemination of information workshop 25 Brussels, February 2008 Dissemination of information workshop 26 Remark:The decks corresponding to L 1 or to L 2 may have additional supports. L 1 max. or L 2 max. without expansion joints: 90 m (concrete, composite) 60 m (steel), but: L 1 + L 2 = 180 m/ 120 m with fixed bearing in the middle!!!!!! For new bridges even if taking α = 1,33 for ULS design note: a slightly overdesigned bridge for ULS has less fatigue problems if the loadings do not increase!) - fatigue assessments are done with the load model LM 71 and α = 1,00. In supplement, the calculation of the damage equivalent factors for fatigue λ should be done with the heavy traffic mix, that means waggons with 25t (250kN) axles, in accordance with Annex D of EN Safety verification for steel structures (Real) train types for fatigue Brussels, February 2008 Dissemination of information workshop 27 Brussels, February 2008 Dissemination of information workshop 28 γ Ff σ c γ FfλΦ2 σ 71 γ is the partial safety factor for fatigue loading Mf Example of a train (no( 1 of 12 given types of trains): λ Φ 2 is the damage equivalence factor for fatigue which takes account of the service traffic on the bridge and the span of the member. Values of λ are given in the design codes. is the dynamic factor (see of EN ) σ 71 is the stress range due to the Load Model 71 (and where required SW/0) but with α = 1, the loads being placed in the most unfavourable position for the element under consideration. σ C is the reference value of the fatigue strength (see EN 1993) γ Mf is the partial safety factor for fatigue strength in the design codes Damage equivalent factors for fatigue Brussels, February 2008 Dissemination of information workshop 29 General remarks concerning the fatigue of railway bridges Brussels, February 2008 Dissemination of information workshop 30 λ is the damage equivalence factor for fatigue which takes account of the span, the service traffic, the annual traffic volume, the intended design life of the structural element and the number of tracks. λ = λ 1 λ 2 λ 3 λ 4 where: λ 1 is a factor accounting for the structural member type (e.g. a continuous beam) and takes into account the damaging effect of the chosen service traffic (e.g. heavy traffic mix), depending on the length of the influence line or area. λ 2 is a factor that takes into account the annual traffic volume. λ 3 is a factor that takes into account the intended design life of the structural member. λ 4 is a factor which denotes the effect of loading from more than one track. Values of λ are given in the design codes. General: It cannot be stressed often enough that railway bridges must be designed and constructed in a fatigue-resistant way. For having optimal Life Cycle Costs (LCC) and for reaching the intended design life of minimum 100 years, all important structural members shall be designed for fatigue! Rules for steel bridges: Constructional details have to be chosen and found which give the maximum possible fatigue detail categories σc, e.g.: Composite girders: detail category 71 Welded plate girders: detail category 71 Truss bridges: detail category 71 at sites where fatigue is a risk / detail category 36 at sites where fatigue is no risk. 5

94 nt > 1,2 n0 v/n0 (v/n0)lim General remarks concerning the fatigue of railway bridges Brussels, February 2008 Dissemination of information workshop 31 General remarks concerning the fatigue of railway bridges Brussels, February 2008 Dissemination of information workshop 32 Rules for reinforced bridges: For reinforced railway bridges the fatigue strength categories σs must of course be observed. Welded joints of reinforcing bars should be avoided in principle in regions with high stress variation. The bending radii of reinforcing bars must be big enough to avoid too much loss of fatigue strength. Rules for presteressed bridges: Fully prestressed bridges under service loads have no fatigue problems. For not fully prestressed bridges under servic loads the permissible stress σ s must be observed as well for the prestressing steel as for the reinforcing bars. Plastic ducts can increase fatigue resistance of prestressing steel and electrically isolated tendons permit to assure the quality with long term monitoring. Anchorages and couplers for prestressing tendons have to be placed such that they are in a region of low stress variation. Practical note for bridge competitions Brussels, February 2008 Dissemination of information workshop 33 Permissible deflections Brussels, February 2008 Dissemination of information workshop 34 Personal advice: Bridge competitions should be carried out in two phases. The first phase should be anonymous with only few calculations and plans called for. The second phase should however not be anonymous. In this phase it is essential, from the owner s point of view, that recommendations for the importent aspects of the design are provided. These include avoiding, where ever possible, expansion joints in the rails near the bridge and, very important, excluding poor constructional details which will lead to fatigue problems. In EN 1990, Annex A2 [2] only minimum conditions for bridge deformations are given. The rule does not take into account track maintenance. A simplified rule for permissible deflections is given below for trains and speeds up to 200km/h, to avoid the need for excessive track maintenance. In addition, this simplified rule has the advantage, that no dynamic analysis is necessary for speeds less than 200km/h. For all classified lines with α >1,0, that means also if α = 1.33 is adopted for ULS, the following permissible values for deflections are recommended, always calculated under LM71 + SW/O, multiplied by Φ, and with α = 1.0: V<80 km/h δ stat l / 800* *Note: Due to what is said in see A [2], namely that the maximum total deflection measured along any track due to rail traffic actions should not exceed L/600, please note that 600 multiplied with 1,33 gives approximately V 200 km/h δ stat l / (15V 400)** ** Note: The upper limit l/2600 for 200 km/h is the permissible deflection which DB has taken during many years for designing bridges for high speed lines in Germany, with satisfactory results. It is also the formula which you can find in the Swiss Codes (SIA 260). V > 200 km/h The value determined by the dynamic study, but min. δ stat l / 2600 Flow chart Figure 6.9 of EN Figure A2.3 of EN 1990, Annex2 Brussels, February 2008 Dissemination of information workshop 35 Brussels, February 2008 Dissemination of information workshop 36 Flow chart for determining whether a dynamic analysis is required. no For the dynamic analysis use the eigenforms for torsion and for bending no Eigenforms for bending sufficient Dynamic analysis required Calculate bridge deck acceleration and ϕ dyn etc. in accordance with (note 4) START V 200 km/h no Simple structure (1) yes L 40 m no no yes yes Continuous bridge (5) no yes (9) no n0 within yes limits of X Figure 6.10 (6) yes Use Tables F1 and F2 (2) (2) (3) (7) yes Dynamic analysis not required. At resonance acceleration check and fatigue check not required. Use Φ with static analysis in accordance (9) If the permissible deformations given just before are respected - taking into account track maintenance - no dynamic study is necessary for speeds 200 km/h.. You can forget the following conditions with the recommended permissible deflections given above: 6

95 Risk scenario to avoid: Brussels, February 2008 Dissemination of information workshop 37 Collapse of railway bridge over the river Birs in Münchenstein, Switzerland, the 14 th June 1891, by buckling of the upper flange under an overloaded train, 73 persons were killed, 131 persons more or less injured. => Tetmajers law. 7