Kræftens Bekæmpelse Hejmdal

Transcription

1 MAIN REPORT Bachelor Project Structural Design 13 th December ECTS Hejmdal & Simpson Strong-Tie Research PRO BP2 Mark Wallis, Sinam Wahab The following document contains reports, calculations and solutions with regards to the structural design of Hejmdal and research of Simpson Strong-Tie brackets.

2 Main Report Hejmdal Project Disclosure Title: Hejmdal VIA UC HORSENS Project period: to Delivery date: Group: Supervisors: PRO BP2 Ander Søvsø Hansen Pauli Andreasen Group: PRO BP2 Mark Wallis Sinam Wahab Page 2 of 65

3 Main Report Hejmdal Preface The following project is the bachelor project for Wallis & Wahab. The project focuses on different areas within structural engineering and combines a main project building as well as research. The project aims to be of a standard that reflects what is expected in industry and documented in accordance to SBI 223 for structural documentation. This project has been a collaboration of two main tasks. Firstly the structural implementation of a building and secondly research of building brackets. The two parts of the project are made separately from one another and there is no interaction between them. The main report provides the overall discussion of the problems addressed, where each report can be read in conjunction with its corresponding annex found in A2. All annex numbers are clearly stated at the start of each report and references to other annexes are clearly stated where required. In many cases the work carried out is performed by a particular member of the group, in these cases the group members initials are clearly displayed both in the title of the report and in the contents of the project. The following initials represents the group member as follows: MAWS Mark Wallis SIWA Sinam Wahab Wallis & Wahab would like to thank Anders Søvsø Hansen and Pauli Andreasen for their continued support and assistance throughout the project phases, Hans Erik for assistance with regards to performing of lab research and Simpson Strong-Tie for financing the research. Page 3 of 65

4 Main Report Hejmdal Abstract This project covers several disciplines within the structural specialisation of civil engineering. A variety of different skills and materials have been used for the completion of the project, which can be summarised below: Stability Design Concrete Structures Steel Structures Masonry Structures Timber Structures Wallis & Wahab have worked collectively throughout the project as many areas of the project have required close coordination. The choice of building is due to inspiration for a project after a chance visit to the building. The project building has provided a significant challenge that covers a variety of different building materials and design approaches. All solutions found in this project have been designed in accordance to Eurocodes and corresponding Danish National Annexes or manufacturers recommendations. Page 4 of 65

5 Main Report Hejmdal Table of Contents Project Disclosure... 2 Preface... 3 Abstract... 4 Introduction... 6 Hejmdal... 6 Research Simpson Strong-Tie... 7 Global Stability... 8 External Structure... 8 Internal Structure Entrance Structure Extension Stability Modelling Finite Element STAAD Pro 3D Model of roof structure SIWA STAAD Pro 2d Model by MAWS Roof Structure Design of Primary Beams (Outer) by SIWA Design of Secondary Beam (Outer) by SIWA Design of Secondary Beam (Inner) by MAWS Design of CHS Profile - by MAWS External Structures Design of Masonry Walls - by MAWS Design of Concrete Corner Section by SIWA Design of Retaining Wall by SIWA Proposal for Steel Extension Structure - by MAWS Connection Secondary Beam to Wall by MAWS Connection - Concrete Corner by SIWA Conclusion Literature List References Page 5 of 65

6 Main Report Hejmdal Introduction Hejmdal The building in this project is named Hejmdal and is located at Peter Sabroes Gade 1, Aarhus, Denmark in the vicinity of the district hospital. Figure 1 - Location of building The building has been specifically designed for an organisation called Kræftens Bemkæmpelse, who are a support group for those effected by cancer. The building is designed as their new headquarters in Århus and has a very unique design. Internally the building is dominated by huge timber structures that form the basis of the roof and the two floors of the building. Externally the building consists of masonry walls a glazed roof and glazed extensions that from an attached entrance structure. As the purpose of the building is to support those suffering with cancer, the philosophy of the building is that it should create an atmosphere that is unique, tranquil and calming. This explains the use of huge timber beams and columns and the separation of the internal and external structure. The uniqueness of the design of this building provides many challenges from a structural perspective. Figure 2 - Internal Structure Page 6 of 65

7 Main Report Hejmdal Research Simpson Strong-Tie A major part of the project is also the research into steel building brackets made by Simpsons Strongtie. The subject of the research is two angle brackets that are increasingly being used to attach windows to facades in small house constructions. The two subjects of the research are brackets: AH9035 VIG40417 Figure 3 - Detail of brackets and picture In this project a series of experiments have been conducted to establish the limits of using these brackets with the set up that is given by the client Simpson Strong-Tie. The experiments have been conducted at VIA University Horsens in an agreement with Simpson Strong-Tie. It should be noted that this part of project has been written in Danish as the required language for delivery. The main report does not contain any of the information concerning the research, which can be found in the annexes as a separate report. Page 7 of 65

8 Main Report Hejmdal Global Stability The stability design of the building Hejmdal provides a variety of interesting challenges with respects to the transfer of forces to the foundations. The structure can be sub divided into different categories. The figure below shows a plan view of the entire building, whereby these following areas of the building can be seen: External Structure Internal Structure Entrance Structure Extension External Structure Extension Entrance Structure Internal Structure South North Figure 4 Plan of ground floor External Structure The external structure consists of the external walls which are made from concrete up to terrain level and then masonry to the roof level. There is also concrete strengthening of the masonry walls in the corners of the building where the primary roof beams are connected. Figure 5 Sketch of external structure Page 8 of 65

9 Main Report Hejmdal The roof structure is made from large timber beams. These timber beams are classified as the following: (next page) Primary Roof Beams Span from each corner of the building and are used to support the large CHS profile in the top of the roof. Secondary Roof Beams Span from the façade walls to the CHS profile in the top of the walls. Figure 6 (Left) Primary Beams, (Right) Secondary Beams Hip Beams Connect with the primary beams in the corners of the building and the two outer secondary beams. These provide extra support to transferring longitudinal wind loads. Cross Beams Span between the primary beams at each gable end and contributed to an even distribution of wind load transfer on the gable roof. Purlins HE profiles are used to provide a connection with the glazed roof panels that will then form the outer shell of the roof. Figure 7 Roof with hip beams, primary beams and secondary beams. Page 9 of 65

10 Main Report Hejmdal Wind Load Transfer - Roof Construction The following section will include a brief explanation of the global stability in the roof structure, when effected by horizontal forces (wind). The glazed roof is supported by numerous timber and steel beams. Figure 8 shows the plan view of the bearing elements of the roof structure. Figure 8 - Structural roof plan As mentioned before the roof structure consists mainly of glass. The glazed roof structure is supported by steel HEB-profiles, these beams are then supported by the timer beams (TB). The timber beams which are supported vertically on the facades are also connected to the circular hollow section. The circular hollow section is the center of the roof structure and is supported by the primary beams (PB). The timber beams which are mentioned in this section can also be referred to as Secondary beams in the coming sections. In the corners of the building L-shaped concrete walls are supporting the primary beams and thereby also the whole roof structure. The Primary beams at each corner are all tied together in the bottom with a steel tie to take the expected large horizontal reaction (see Figure 9) also explained later. Figure 9 - Roof ties Page 10 of 65

11 Main Report Hejmdal Wind in the transverse direction: With wind in the transverse direction, 2 types of wind contribution have to be taken into account. Wind in the transversal direction from the façade and wind in the transversal direction from the roof. Both situations will be explained with words and sketches as precise as possible in the later sections. Wind transfer from the façade: When the wind acts upon the masonry wall, half of the wind from the façade will be taken in the timber beams (TB) as an axial force and the other half will be transferred to the foundations, see Figure 11. The axial force will then be transferred to the circular hollow section (CHS) which are supported by the primary beams. The load transfer of the wind in a 2D plan can be seen in Figure 10. The load transfer from wind on the façade can be seen in Figure 12. As seen on the figure, the ties are in action at this point. These sketches below show the internal forces in the roof structure. It is important that the internal forces in the roof structure are in equilibrium. Without this, the structure will collapse. Just as important it is for the internal forces to be in equilibrium, it is just as important that the external forces in the roof structure are in equilibrium, this will be explained in a later section. Figure 10 - Static model CHS Figure 12 - Wind on facade Figure 11 - Wind on facade Page 11 of 65

12 Main Report Hejmdal Wind transfer from wind on the roof: Apart from wind on the façade the roof structure will also be effected by wind directly on the roof. The glazed roof structure will be transferring the wind load to the HEB-Profile (HEB - profiles highlighted with blue in Figure 13, and thereby to the timber beams and primary beams. Two different static models of the roof structure have been discussed. Bending and axial force can occure in the different element by wind on the roof structure. Figure 14 - Wind on roof Figure 13 - HEB profiles As the roof structure is very complex and hard to get an idea of the stabilizing system we have made the decision to use some of our time to make a real life 3D model of the structure. This also includes the internal structure of the building. Also a 3D finite element model of the structure has been done and analyzed to see if this lived up to expectations, which it did. The sectional forces have been taken from the program and been used for dimensioning of the different elements. 2 models are considered for the stability of the roof structure: 1. Using the primary beams and the circular hollow section as a 3 way portal frame. This will help on the overall deflection of the structure. 2. Only using a pined static model, where the hip beams and the HEB profiles will be the stabilizing system of the roof structure. For more info regarding this can be found in section 2D Model Page 12 of 65

13 Main Report Hejmdal Wind in the longitudinal direction: According to wind on the gables it is worth mentioning that wind on the facades will be transferred to the diaphragms in the internal structure. In this section we will only concentrate on wind in the longitudinal direction effected on the roof structure. The load transfer can be seen in Figure 15. The load transfer in the roof structure as for wind on the gable is very simple, the glazed façade will transfer the wind to the HEB-Profiles, highlighted on Figure 16, this is then delivered to the primary beams highlighted on Figure 17. The primary beams are connected to two beams in the longitudinal direction, the circular hollow section and the HEB-Profiles. The hip beams will be exposed to a tension and compression force. Similar to wind in the transversal direction the ties are also in action at this point. The function of the ties can also be seen on Figure 9 on the first page of this section. Figure 15 - Longitudinal wind transfer Figure 17 - Primary beams Figure 16 - HEB in gable roof Page 13 of 65

14 Main Report Hejmdal External Forces As mentioned before it also important that the external forces of the roof structure are in equilibrium, this we will make sure of by having the L-shaped concrete walls to work as a shear wall. Figure XX And figure XX shows how the system will work. This is the case with both wind load in the transversal direction and for wind in the longitudinal direction. The load of these can be found by the overall wind load on the roof structure divided with 4 walls. More about this can be found in the section about concrete corner sections. Figure 18 - Concrete sections (transverse) Figure 19 - Concrete sections (longitudinal) Page 14 of 65

15 Main Report Hejmdal Wind Load Transfer - Walls Wind on Gable Walls One of the major concerns in the stability phase of this project has been how the walls transfer loads to their designated paths. As mentioned before the walls are made from concrete between foundation and terrain level and from masonry between terrain level and roof level. It is also worth mentioning that that terrain level has a difference of 1,35m from the north to south end. The basement wall will be built to the highest terrain level and a brick render used where the basement wall is exposed above terrain level. Both gable walls have been analysed to establish an approximate load path of the wind loads to the foundations. North Gable 4.4m 7.3m Figure 20 North Gable 15m Page 15 of 65

16 Main Report Hejmdal The first problem encountered with wind loads on the gables is how the walls are supported with so many openings. It can be seen that there are a couple of windows and doors as well as a large opening in the wall for the frame structure. Secondly in the roof structure there is only a connection with the roof in the corners of the gable, where the primary beams of the roof have a connection. Therefore meaning that the wall has a free edge along the top side. Lastly, although there are two diaphragms in the internal structure that can be used to take some loads, they cover only a small length over the wall and therefore the walls ability of distributing the wind to these areas will need to be investigated. The figure below shows the conditions for the north gable wall, with the positions of the two diaphragms also marked by red hatchings. This gable wall is split into parts A and B Wall support 1 st Floor Diaphragm - Masonry -Concrete Façade Wall A B Terrain level Ground Floor Diaphragm Figure 21 North Gabel support system Page 16 of 65

17 Main Report Hejmdal For the wall to have adequate support it will be necessary to include a system to limit the spans and length of the masonry wall. An example could be to use steel profiles to support the brick work as shown in the figure above, however other solutions such as post tensioning will also be considered in the dimensioning process. To provide support at the top of the wall, a beam will be placed that has a connection with the steel frame construction. These beams on top of the walls are present on all façade gable walls. (Figure 23) Frame profile North west gable Figure 23 - U profile on the top of wall U profile on wall NOTE! By referring to the report on stability of the horizontal load on the roof, one should be aware of the fact that although this connection is made on the top off the wall, its primary function is to only transfer wind loads from the wall up into the roof, not from the roof to the wall in the case of wind suction. In this case the horizontal component is transferred to the CHS profile in the roof and to the concrete corner sections via the primary beam system. (Figure 22) Figure 22 - Principle of no wall reactions It must also be noted that there are no beams in the roof at the gable ends and therefore there can be no transfer of wind from the gable walls through the roof. Instead all of the forces must be either taken to the adjacent facade walls, the two diaphragms marked in Figure 21. or the frame structure via the beams on top of the walls. With respects to the concrete part of the wall that is under terrain level, there are also some problems that need addressing. Firstly there are no diaphragms on the inside of the wall below this level, so looking from the inside of the building the wall height is from the basement floor to the 1 st floor! Retaining wall The lateral load on the wall therefore not only includes wind load but also soil pressure on the backside of the basement wall. The solution for this problem for the entire building is to construct a retaining wall Insulation behind the basement wall that will relieve the main structure of this extra soil pressure as shown (right). A connection is also made between the retaining wall and basement wall. Brickwall Concrete wall Basement floor Foundation Figure 24 Cross section Basement / Terrain level Page 17 of 65

18 Main Report Hejmdal South Gable Many of the same principles also apply to all facades. This includes anchored basement concrete walls with retaining walls to take soil pressure, as well as wall supports in the form of steel profiles. For the south gable these principles are also shown: Figure 25 South Gable 5,8m Note The masonry walls all have a height of 4,4m. All walls under terrain level will be supplied with a render to achieve the correct appearance where necessary. 15m Page 18 of 65

19 Main Report Hejmdal Wall support 1 st Floor Diaphragm Figure 26 - South Gable support system Ground Floor Diaphragm Wind on Façade Walls The façade walls will follow the same principles as explained above for the two gables. This includes using some wall supports to reduce the free area of the masonry walls. The wind load can be successfully distributed to the foundations and roof. The main difference between the facades and gables is that the facades have the roof to also transfer wind loads. The beam profiles that sit on top of the walls will have a connection with the secondary beams in the roof. The transfer of wind loads will be via the roof and foundations instead of with connection to the diaphragms, which are only found in the gables. Page 19 of 65

20 Main Report Hejmdal Internal Structure The Internal structure is a very unique structure that is also made primarily from timber beams and columns. Beams are connected together to support the floor areas and then columns with a variety of different spans and angles support these floors around the perimeters. Due to the complicated nature of this structure, a model in the scale 1:50 has been made, which is the best way to gain an overview of the structure. (See pics) Figure 27 Model of Internal structure The idea with this structure is that the floors work as diaphragms, which can transfer horizontal mass loads to the slanted columns. As most of the columns are standing at an angle, they will also be designed to take a horizontal force. Under the first floor there are also a series of concrete walls that will be used as shear walls. The internal structure will take wind loads from the gable walls of the external structure through connections with the diaphragms at ground, and 1st floor level. Entrance Structure The entrance part of the building is fully glazed and is supported by a steel portal frame structure. This structure also contains the main stairway for the building. The frames are designed so that they are able to take moments in both directions, thus giving this part of the structure its independent stability. Extension The extension in the north end will be considered both as a simple frame structure with wind bracings, but also similarly to the extension in the entrance structure with two way frames. A proposal for this structure can be found later in the report. Page 20 of 65

21 Main Report Hejmdal Stability Modelling Finite Element STAAD Pro 3D Model of roof structure SIWA ANNEX A2.1.3 When the static system of the roof structure has been executed based on an initial evaluation, it is important to ensure that the structure will act as estimated. A 3D STAAD Pro model of the roof construction has been carried out to give a better understanding of how the structure will work in space, which of course has to be held up against the requirements. A 2D model of the structure has been completed to give a better understanding of the structure in plane view. In this section the focus will be on the 3D model. This section will include a brief explanation and conclusions based on the STAAD Pro model and on the expectations, all data can be found in ANNEX A2.1.3 Problems in modeling process: When modeling the structure in STAAD Pro a few problems did occur which made the process a little bit more complex than expected. Figure 28 shows the system of the structure, the elements marked in blue are the HEB-profiles which lies on top of the Secondary beams and the primary beams. The modeling of these beams have been a challenge as it is not possible to model an element on top of another element in STAAD Pro. The HEB-Profiles transfers the self-weight of the roof structure and the wind loads to the secondary beams and it also prevents the secondary beams from buckling in the x direction, so the HEB-profiles are very important and cannot be neglected. A few ways of solving this problem have been investigated. Figure Removing the HEB-profiles and inserting supports in the X direction and Inserting the self-weight of the roof as point loads on the secondary beams. 2. Placing the HEB profiles between the secondary beams with moment releases by the secondary beams, this should help the wind load in the longitudinal direction to transfer through the construction. One of the reasons why a finite element model is much easier to work with is, because of the different load combinations that has to be checked, to find the worst load case to dimension the elements from. Please note that a small mistake has occurred in the load combinations where internal pressure and suction has not been added in, this of course also needs to be checked. All loads are in accordance to ANNEX A2.7.4 and can also be found in ANNEX A2.1.3 with explanations. The following load combinations are investigated: Page 21 of 65

22 Main Report Hejmdal 1. 1,5*WT+1,0*G (Max wind transversal + Self weight) 2. 1,5*WL+1,0*G (Max wind longitudinal + Self weight) 3. 1,5*WT+0,9*G (Max wind transversal + smallest self-weight) 4. 1,5*WL+0,9*G (Max wind longitudinal + smallest self-weight) 5. 1,2*G (Only self-weight) The models on STAAD Pro have been very exciting and interesting to work with, as to how changes in the roof structure can affect the whole system. Changes have been made to the models to ensure the most optimized structural system. It shall be noted that in the modeling process all the secondary beams are provided with simply supported support (see Figure 31), taking into account that the support cannot take a reaction acted as suction. Figure 29 shows the reactions from wind on the façade allowed (Green arrows) and the reactions from suction based on the wind which is not allowed (Red arrows). The red arrows which cannot be taken in the connection with the façade has to be transferred through the secondary beams and thereby to the CHS profile which leads it through to the supports (See Figure 30). More about the load transfer can be found in the section about global stability load transfer. Figure 31 supports Figure 29 - forces Figure 30 The following different 3D models have been investigated: A. Roof construction with support systems in the secondary beams (instead of HEB profiles) B. Roof construction with HEB profiles between the secondary beams (to transfer the horizontal load) C. As B with glulam instead of solid wood D. As B and C with primary beams as steel beams E. The most stabile system chosen with bracings Page 22 of 65

23 Main Report Hejmdal A. Roof construction with support systems in the secondary beams (instead of HEB profiles) As mentioned before the HEB profiles cannot be modelled as wanted, that s why a decision was made to replace these HEB profiles with supports in the x direction as seen on Figure32 (red marks by supports) Figure 32 - Model of situation A Figure 33 - Movement in model A Figure 33 shows right away that this model was incorrect due to movement in the system. With the supports in place the deflection where the HEB profiles and the secondary beams meet are equal to zero which will not be the case. Next model is then investigated. B. Roof construction with HEB profiles between the secondary beams (to transfer the horizontal load) In difference to model A, model B has HEB profiles between the secondary beams so that they can transfer the horizontal load applied from the wind on the gable. This way we also insure movements in the secondary beams which was not the case in model A. The HEB profiles between the secondary beams are released for moments at every end. Figure 35 Figure 35 - Model B Figure 34 - movement model B Figure 34 shows the deflected structure when exposed to longitudinal wind. As seen movement in the secondary beams occur. It shall be noted that the marked area in the figure shows a wrong deflected form in the hip beams and the HEB profiles. Realistically the HEB profiles act as a continuous beam and therefor will not Page 23 of 65

24 Main Report Hejmdal deflect as seen. Large deflections are stated in the STAAD Pro program which gave us a deflection of approximately 16 meters. Although this can quickly be seen as incorrect we can still use these deflections as relative deflections to see what can help stiffen the structure. C. As B with glulam instead of solid wood Out of curiosity an investigation using glulam instead of solid wood has been carried out to see if this could help on the large deflections. The model will be as model B and where the only difference will be in the material property. In ANNEX A2.1.3 it can be seen that this does not give the large variation in the deflection. The reason why glulam does not help on the deflection is because the glulam has a weak axis unlike the quadratic solid wood used in model B. D. As B and C with primary beams as steel beams This model is also made based on curiosity, to see how primary beams made of steel can affect the roof structure. This model has been made based on glulam and on solid wood. In the ANNEX A2.1.3 these models can be found as MODEL D1 (Solid wood with steel primary beams) and MODEL D2 (Glulam with steel primary beams). It can also be seen how the deflections are effected by using a steep beams as primary beams. The primary beams and the CHS profile work as a portal frame, if this is made very stiff the Figure 36 whole construction will be much stiffer which results in a smaller deflection. It shall be noted that the hand calculations will not be based on steel beams but solid wood. E. The most stabile system chosen with bracings The most stable system of the above standing models are chosen to stabilize with bracings to see if this can help with the deflection. See Figure 37 for how the bracing system will be performed. It shall be noted that in the ANNEX there is not much difference between a braced system and an unbraced system. A small modeling failure has been detected as the bracing system does not reach its full force. The red marked lines on Figure 37 indicates that the HEB profiles should be removed to ensure that the horizontal force in that direction does not move on. Figure 37 Page 24 of 65

25 STAAD Pro 2d Model by MAWS ANNEX A2.1.2 Introduction Having discussed the main principle of the stability model a finite element model has been made to try and evaluate the way in which the roof structure may move and if these movements will be acceptable. The 2d model concerns the movement of the roof in the longitudinal direction, hence looking at a transverse elevation. The area of interest is whether the introduction of the hip beams can prevent brace the roof structure and prevent unacceptable movements as shown in the figure below: Figure 38-2d model with wind actions Figure 39 - exaggerated movement The idea behind the hip beams as discussed earlier, is to help deliver actions in the direction showed above to the main supports of the primary beams (most left and right supports). This priciple is shown below: Purlins Figure 40 - Principle of Hip Beams Page 25 of 65

26 Loads & Combinations There are some limitations to analysing the roof structure in this way as the true direction of all the forces and reactions can not be modelled completely accurately with a plan view analysis. Some delimitations and assumptions have been made in order to make this type of analysis more accurate: 1. Direction of self weight actions STAAD Pro has a function where self-weight of the members can be automatically applied to the model. The problem is that when modelling 2d this total weight is applied as a y component. As a part fix the load has been to resolve the self-weight so it corresponds to the actual weight applied in the y direction. This obviously also highlights the fact that 2d modelling neglects some aspects of the stability analysis. Figure 41 - Application of selfweight 1. Direction of wind actions The same approach taken for self-weight has also been applied for wind actions. In hindsight STAAD includes a function to have these load as drawn in fig 42 and the model is more than capable of evaluating in this way. This is a minor error and should be corrected. Figure 42 - Application of wind One major drawback to 2d modelling is that although the 2d models give an idea of movement in plan, it does not consider the actions from the other direction (perpendicular to plan). To 2d model is simply to identify the function of the hip beams in securing forces in the investigated case. Load combinations for this individual case are therefore very limited in this case. With pressure on the gables there will be suction on the adjacent side and with pressure on the gables there will be equal and opposite suction on the gables, thus not worst case. Snow load is 0 due to the thermal factor and pitch of the roof. Page 26 of 65

27 The following load cases are therefore taken into consideration: 1,0 G kj,sup + 1,5 W k - With combinations of internal pressure and internal suction Results 1,2 G kj,sup In total 3 different cases were investigated because the movements in the first case seemed to be a little excessive. Therefore measures were taken to try and reduce the total movement. These are stated below: Model A - Loblolly Pine 450mm x 450mm sections for both primary and secondary beams. Model B Frame structure - Primary beams IPE sections, CHS centre section (fixed connection in roof) Model C - Both Primary and Secondary beams of Pine but with hip beams and bracing cables. Annex A2.1.2 gives exact details and parameters for the model. The results can be summarised below: Model Maximum Nodal Movement (mm) A 200 B 36,5 C 48,1 Figure 43 - Max movements These indications of nodal movements will not be 100% accurate, however it gives a good indication of systems that are likely to be appropriate. The architect s proposal could prove to be problematic in meeting deflection requirements. Given that the roof is glazed, it would be wise to consider options that may limit movements. Although a solution with a fixed steel frame provides the minimum deflection in the model, it compromises the design significantly and the connections could be very complicated and expensive. Page 27 of 65

28 Roof Structure Design of Primary Beams (Outer) by SIWA ANNEX A2.2.1 In the following section the focus will be on the primary beams. Figure 44 shows where the primary beam is located in the roof structure (primary beam is marked in blue). The stability of the roof structure is explained more detailed in the section called Global stability. The calculation for the primary beams will be based on the stabilizing model where the primary beams and the CHS profile forms a 3 way portal frame. This means that the elements included in the frame structure should be able to take moments at the ends (see Figure 44, the static model of the primary beam). Figure 44 Also on Figure 45 a 3D model of the frame structure can be seen. It is also seen how the crossbeams are supporting the primary beams against buckling in the giving direction. The timber used in this construction is a special type of wood called Loblolly Pine which the architects have wished for, for the aesthetic reasons. It is also worth mentioning that the giving dimensions of the beams which are 0,45x0,45 m are exaggerated, but also this is the wish of the architect. More about the architects wishes can be read previous in this report. Figure 45 Page 28 of 65

29 All 4 primary beams are supported by concrete wall corners which will be dimensioned to take the vertical and the external horizontal load, as we remember the internal horizontal forces in the primary beams will be taken by the steel ties provided as mentioned before. The static model of the primary beams can be seen on Figure 46. Figure 46 The wind loads on the beam have been calculated in accordance to ANNEX A The different load combinations depending on wind transverse, wind longitudinal, internal pressure and internal suction have been examined to find the worst case scenario and dimension the beam based on these. In the first pages in ANNEX A2.2.1 you can find the different load combinations and of which is the worst. The worst case load the primary beams are subjected to is wind in the longitudinal direction, and in the pressure zone as seen on Figure 47 (zone marked in red). In the corner the primary beam will be subjected to pressure, and with internal pressure and self-weight which acts in the same direction this will be the worst case. Figure 47 The roof structure is made of glazed panels as mentioned in the previous sections. The self-weight of these have been calculated based on the material data given by VELFAC in ANNEX A Because of the large angle (54 degrees in the facades and 60 degrees in the gable) and the material the roof structure it is made by, snow load will not affect the structure in any way. 1. Because of the heat transfer through the windows 2. Sliding because of the large angle When the load combinations have been carried out a finite element model of the structure have been made to find the stresses in the primary beams as well as in the CHS profile. Loads on the CHS profile have been provided from ANNEX A2.2.4, and this will not be explained any further in this section. Page 29 of 65

30 Figure 48 The diagrams above are given from the STAAD Pro program. The stresses have been taken from the program and are used to verify the dimension from. It is also seen that the diagrams indicates bending around two axis s which will influence the dimensioning process. The dimensioning process have been in accordance to DS/EN and Træ og Trækonstruktioner 2. This process includes the following : - Check of axial load alone - Check of Axial load and bending around two axis s - Check for lateral torsion in columns - Check for shear - Check for torsion - Check for deflection All calculations indicates that there will be no problems with the material and its size. A further investigation could be done as for an optimized dimension of the beams, of course this also needs to be approved by the architect. Page 30 of 65

31 Design of Secondary Beam (Outer) by SIWA ANNEX A2.2.2 The following section will include a brief explanation of the dimensioning process of the outer secondary beams. The secondary beams are placed as showed in Figure 49. A dimension of these and a dimension of the inner secondary beams have been made (secondary beams ANNEX A2.2.3). The difference between these two beams are simply the load area which they need to resist. PRO BP2 -Main Report The dimensioning process regarding the outer secondary beams are very similar to the primary beams and the inner secondary beam, only some small facts are in difference, and only these will be mentioned in this section. Figure 49 Unlike the primary beams, the secondary beams will be simply supported in the top and bottom (see Figure 50) kept in mind that the reaction on top of the façade is not able to take a horizontal force, this modelled in STAAD Pro. The load combinations have been carried out in the same way, but the secondary beams will only take load from wind of the roof in the transversal direction. The loads and their acting direction can be seen on Figure 51. The beam will be effected in two directions as seen in the figure. When looking at the front view the beam has to resist a small wind force from win in the gable. Else the only thing that will affect the beam when looking at the side view will be wind load and self-weight. Figure 50 Figure 51 Page 31 of 65

32 The stresses taken from the program is as shown below. Side View Front View Deflection: Moment diagram: Shear forces: Axial force Page 32 of 65

33 The diagrams above are giving from the STAAD Pro program. The stresses have been taken from the program and are used to verify the dimension from. It is also seen that the diagrams indicates bending around two axis s which will influence the dimensioning process. The dimensioning process have been in accordance to DS/EN and Træ og Trækonstruktioner 2. This process includes the following: - Check of axial load alone - Check of Axial load and bending around two axis s - Check for lateral torsion in columns - Check for shear - Check for torsion - Check for deflection The ANNEX indicated that all checks are verified for the load applied. Page 33 of 65

34 Design of Secondary Beam (Inner) by MAWS ANNEX A2.2.3 PRO BP2 -Main Report The secondary beams are described by the timber roof beams that are connected from the masonry walls to CHS profile in the top of the roof. These can further be classified by either inner or outer beams, which depends on the loads that they are subjected to. The figure below explain this classification: The only main difference in the load that these two beams carry is the wind load area. Figure 52 - Secondary Inner Beams For calculation of these beams it is first important to establish the model. As previously discussed it is important that the walls are not subjected to horizontal loads at the top. The solution for this is that the CHS profile takes these horizontal loads as it forms a base structure with the primary beams for the secondary beams. (See stability report) The model for the calculation of these beams is show below: Support Conditions: pin in top CHS, roller in the bottom Wall. Please note that in reality, the pin support at the top will behave more like a spring as this CHS profile will also undergo a deflection under load. It is important therefore that the CHS profile is dimensioned for very small deflections. Page 34 of 65

35 Loads The beams are subjected to a series of point loads explained below: W1 and W2 Wind loads from the purlins. HE profiles span across the roof and deliver the wind loads from the glazed roof panels at these two points. W3 and W4 Wind loads from load on the gable. W4 is not shown on the sketch as it is taken directly to the hip beams, W3 is distributed along the 8 secondary beams. W5 and W6 Wind Loads from the supports on the wall and CHS. W6 is delivered directly to the CHS profile in the top of the wall and W5 to the lower part of the beam. W w Wind Load from the wall. Wind loads from the façade are delivered to the secondary beams here. G 1 Self weight of the secondary beam. G 2 Self weight of the glazed roofing delivered by the purlins. Load Combinations All load combination involve cases of wind and self-weight leading. The roof structure is not subjected to any snow loads on this section, due to the pitch of the roof and the thermal transmittance coefficient. Nevertheless there are many cases of wind that must be considered which are summarised below: W1.f.p Transverse wind on the roof with positive internal pressure. W2.f.s Transverse wind on the roof with negative internal pressure W1.g.p Longitudinal wind on the roof with positive internal pressure W2.g.s Longitudinal wind on the roof with negative internal pressure For all load cases the characteristic actions must be considered on the front side and back side of the roof. In the load calculation front and backside loads are indexed as W f & W b respectively. (Sketch next page) Page 35 of 65

36 Figure 53- clarification of roof sides After completing combinations for wind, it could be seen that the worst case is W2.f.s on the front side with transverse wind combined with negative internal pressure. This load combination is then combined with self weight for the following combination in accordance with DS/EN Wind Leading 1,0 K FI G kj,sup + 1,5 K FI W 2.f.s 2. Self weight Leading 1,2 K FI G kj,sup 3. Servicability 1,0 G kj,sup + 1,0* W 2.f.s Note the load is separated for calculating deflection in timber Design The calculation of this secondary beam is to check that the dimensions specified by the architect are sufficient enough. The design of the building requires large timber sections that match with the internal structure, these dimensions are not specified on load bearing capacity of the roof but simply on an aesthetical basis. The chosen dimensions of the roof beams: The material of the timber is also specified by the architect as loblolly pine, details of which can be found in annex A4.2. All strength parameters regarding this species are taken from the works of David W. Green, Jerrold E. Winandy, and David E. Kretschmann. (See references). Page 36 of 65

37 Calculations Several calculations are completed for these members, all of which are performed in accordance with DS/EN and the Danish national annex. The following calculations can be found in Annex A2.2.3 Ultimate Limit State Column subjected to combined bending and axial compression (6.3.2) Lateral torsion beam subjected to combined compression and bending (3.3.3) Shear (6.1.7) Torsion (6.1.8) Serviceability Limit State Deflection (2.1.2) Limits of deflection in secondary beams l/300 = 36mm (table 7.2 EC5) Conclusion On completion of the calculations it can be seen that the dimensions of the beams specified by the architect are sufficient. It must be noted that these dimensions are somewhat excessive it terms of ULS calculations as the capacities of the members are much higher than the design loads they are subjected to. Nevertheless in SLS, the deflection is closer to the limits decided. The total deflection was calculated to 16,7mm This is in accordance with the lowest and highest recommended limits of deflection, stipulated in EC5 l/300 = 11/300 = 37mm l/500 = 11/500 = 22mm It can be seen however that in terms of deflection the beams are reaching their capacity and therefore if a square cross section is required, the choice in section size is perhaps justifiable. It would be more economic perhaps to use a cross section with a different b/h ratio, as the height is what contributes most to the 2 nd moment area not the breadth. Page 37 of 65

38 Design of CHS Profile - by MAWS ANNEX A2.2.4 The main roof beam that is responsible for supporting all of the secondary beams will be dimensioned as a circular hollow section. The reason for using a CHS profile are as follows: CHS section will be subjected to loads from different directions, as the profile has the same properties in each direction, design is much easier. Hollow sections are also less susceptible to the effects of torsion and lateral torsional buckling. Connection of timber to the CHS can be accomplished by welding steel plates to the CHS section. Aesthetically pleasing and requested by the architects. A sketch of the profile can be seen below: Figure 54 - Sketch of CHS from two perspectives Firstly it can be seen that CHS profile is supported by the two primary beams at either end. There were two proposals discussed in stability. The first where the CHS forms a fixed frame structure with the primary beams and secondly, where the CHS is simply supported by the primary beams and stability is achieved by the use of hip beams and other bracings. Due to the complex nature of a frame calculation between timber and steel members, as well as complicated moment connections, the chosen proposal is one where the CHS is simply supported at either end. Page 38 of 65

39 The static model for the design of the CHS profile has therefore been taken as the following: Figure 55 Loads on the CHS From figure 24, it can be seen that the secondary beams do not meet the CHS in a line from both sides, but are staggered instead. When finding the loads, the model was simplified and it has been assumed that the beams are in line. Staad pro has been used to model different load combinations of wind and self-weight on the roof, the model is found below: Figure 56 Loads were applied to the model as point loads, where the purlins are located along the beam. A full description of these loads can be seen both in Annex A2.2.3 and A Page 39 of 65

40 The idea is that from this model a reaction can be obtained in the top support shown in the model, which will be the result of the actions from the secondary beams, in that section. It should be noted for load cases where the reaction consisted of two directions, a resultant was calculated. Although the beams are staggered, on any one side there is a distance between the secondary beams of 1,2m. Therefore this reaction when divided by this distance can be expressed as an action on the CHS per meter. Load Combinations The load combinations considered when modelling this system include all cases of wind leading and selfweight leading : Wind Combinations are described below: W1.f.p Transversal wind with positive internal pressure W2.f.s Transversal wind with negative internal pressure W1.g.p Longitudinal wind with positive internal pressure W2.g.s Longitudinal wind with negative internal pressure The resulting load cases considered are those in accordance with DS/EN Wind Leading 1,0 K FI G kj,sup + 1,5 K FI W 2. Self weight Leading 1,2 K FI G kj,sup 3. Servicability 1,0 G kj,sup + 1,0 From the staad analysis the following results were achieved for global analysis. Load Combination Resultant reaction in top support (kn) 1,0 G kj,sup + 1,5 W 1.f.p 20,3 1,0 G kj,sup + 1,5 W 2.f.s 23,91 1,0 G kj,sup + 1,5 W 1.g.p 24 1,0 G kj,sup + 1,5 W 2.g.s 14 1,2 I G kj,sup 21,5 As the CHS has the same properties in all directions, the direction of this resultant in some ways is irrelevant as the support conditions of the CHS are always the same and the action will always act as a uniformly distributed load. Load combination 1,0 G kj,sup + 1,5 W 1.g.p is determined as worst case. As well as being subjected to bending, the CHS will also be subjected to an axial load from wind effects on the gable. Bending is the critical loading and so different load combinations to include the effect of axial actions were not considered. This is also because the fluctuations in axial forces were also very small. The axial force was determined only for the worst case and is based on the wind load area in the roof on the gable. This calculation can be seen in A2.2.4 Page 40 of 65

41 Calculations When dimensioning the CHS there were two very important aspects that needed to be considered: The diameter cannot become too large due to space requirements in the top of the roof. A limit of 500mm is chosen as the limit of the outer diameter Deflection is very small. 5mm max The secondary beams have been modelled as being supported by the CHS as a pin, in reality this is more of a spring as the CHS can also undergo a deflection. If this deflection is too high then the serviceability calculations of the secondary beams will not be accurate. Initial calculations for dimensioning began with serviceability limit state, where a required I y was calculated to keep deflection below 5mm. On determining the appropriate sizes the moment diagrams etc. were adjusted for the actual selfweight of the beam. CHS dimensions: 457mm x 40mm Large thickness required. ULS calculations The following procedure has been performed to verify the load bearing capacity of the CHS in accordance with DS/EN Determine cross section class cross section class 1 determined 2. Plastic analysis of maximum load before failure Compared with Med 3. Check reduction of M Rd for combined bending and axial 4. Check second order moment is negligible 5. Verification of column buckling. (See Annex A2.2.4) Results The demands for deflection have been the dimension giving requirement for the CHS, there is a large surplus in the capacity of the beam for ULS calculations. All the above calculations have been verified. Further Considerations The connections between the primary and secondary beams to the CHS profile is an area overlooked in this project due to their complicated nature. Page 41 of 65

42 References Bent Bonnerup, B. C. (2009 ). Stålkonstruktioner efter DS/EN Udgave. DS/EN Eurocode 3; Steel Structures. (2007). DS/EN Eurocode 3; Design of Joints. (2007). Olesen, C. J. (2013). Teknisk Ståbi 22.Udgave. Page 42 of 65

43 External Structures Design of Masonry Walls - by MAWS ANNEX A2.3.1 All of the external walls of the main part of the building are made from masonry. The masonry walls are responsible for transferring the wind load. As the building is quite unique it is worth summarising the load path the wind takes depending on which wall is being discussed; Facades Half of the wind load is transferred to the secondary beams in the roof, half to the top of the basement walls. Note Basement wall has a connection with the retaining wall to achieve this support condition Gable There are no beams in the roof on the gable sides, therefore using a system of beams, the wind load is transferred to diaphragms of the internal structure. For the scope of this project the masonry walls in the facades have been investigated, with the assumption that these dimensions are suitable also for the gables. Materials In A the full technical details of the masonry materials can be seen however a summary is found below: Masonry Units: Randers tegl - Category 1 - Group 1 - F b = 20 MPa - Exposure Class = MX3.2 - Density = 1,615 kg/m 3 General Purpose Mortar: - f m = 3,5 MPa Steel Profiles: S235 Page 43 of 65

44 West Façade The west façade is used for the basis of the masonry calculations as it is deemed to be a worst case scenario. The facades, unlike the gables are also subjected to a line load from the roof. In addition the entire length of the wall is subjected to wind and there are many holes for windows. An elevation of this façade is found below: Figure 57 - West facade The approach to this façade is to use stiffening steel profiles to reduce the sections of the wall that are investigated. In A2.3.1, this is described fully however the principle is shown below: Each section of the wall is separated by a steel profiles or adjacent walls and numbered A to F. Each section of the wall is then said to be simply supported around 4 sides. These support conditions are explained on the next page. Figure 58 - west facade sections Page 44 of 65

45 Support Conditions As previously stated, the individual sections of the wall are treated as simply supported around four sides. Arguably some of the supports could be fixed, however for a safe side calculation, they remain calculated as simply supported. Top of wall A U profile is placed on the top of the wall to transfer loads between the wall and roof. It acts as the support for the wall at the top as seen in the sketch below: Figure 59 - Top support of wall The U profile is connected to the wall with anchors that are secured from the inner side of the u profile. Sides of the Wall The sides are supported either by two steel profiles as in the case of wall sections C and D, or by a steel profile and an adjacent wall. Bottom of the wall The problem with this particular building is that there is a basement wall underneath the masonry walls and no floor slabs or diaphragms to give a reaction to the wall. The principle idea is that a small retaining wall is built outside the basement wall that will hold the soil pressure away. A connection is then made between the retaining wall and the basement wall so that the basement wall is simply supported in top and bottom and the masonry is founded on top of the wall. There have been some assumptions made in this area, which are not correct. This is firstly because it has been assumed that the masonry wall and steel profiles can be founded directly on top of the basement wall. In reality this is not possible due to the space required, let alone how the force transfer between the bottom of the masonry and the basement wall occurs. Page 45 of 65

46 Some considerations have been made when making details. Wall Cross Section The cross section that is investigated for all the walls is shown below: Inner Leaf = 168mm Outer Leaf = 108mm Wall thickness = 480mm Loads on the Wall The loads the walls are subjected to, are taken from A1.7.4 and all combinations of wind and internal pressure are considered. The load combinations considered are to establish: Max bending on the wall. Max line loading on the wall. The worst combination of both cases. The cases investigated are: 1. Wind Leading w.2.f.s Transversal wind with negative internal pressure This gives a max wind load of = 0,818 kn/m 2 From the calculation of the secondary beams it can be seen that this corresponds to a line load of approx. = 24kN/m A full summary can be seen in A2.3.1 Other combinations of wind and line load are not considered as the outer sections of the wall are not subjected to a line load but will still be subjected to the max wind load shown above. Other combinations of wind and line load are therefore irrelevant. Page 46 of 65

47 Design Procedure The following tasks have been completed in the verification of the wall dimensioning and are described below: 1. Characteristic Strength values determined in accordance with NCI 2. Wall F examined - Firstly hand calculation for bending is completed and compared to the results from EC6 design. Both results are identical. 3. General Wall tie spacing and wall ties are determined 4. Ties around the steel columns are determined 5. Steel profiles dimensioned based on stiffness to avoid crack moment in the wall 6. Wall sections C, D and E considered These wall sections are designed with EC6 for bending where the moment is distributed based on stiffness. Masonry beams are dimensioned for the inner leaf to take the load over the windows to the strips of masonry between the windows. Completed with EC6 10 courses necessary to achieve shear capacity Inner leaf is dimensioned for vertical load, the sections between the windows are dimensioned for the effect of a line load at the top of the wall and concentrated load from the bearings of the masonry beams above the windows. Capacity in the middle of the wall is breached so a solution if offered in A2.3.1 Figure 60 - Masonry between windows 7. Details of the wall including, ties, placement of the columns, footings are prepared in Annex A3. K2 301 A K2 301 Page 47 of 65

48 Conclusions The dimensions of the wall are generally ok, with the exception of the vertical bearing capacity of the façade wall where the windows are placed (sections C,D and E). As the capacity is only just slightly lower than the design value, then a solution could be to use a masonry unit with a higher compressive strength. There are some limitations to the dimensioning of the walls in this section, as only some limited locations have been checked. The gable also needs to be investigated thoroughly. Other Considerations There are many other factors that will have an effect of the masonry dimensioning in this project, these are summarised below: Concrete Sections in the corner of the building As discussed in stability, the primary bearing system in the roof is supported by concrete L profiles as the sketch shows below: Figure 61 - Sketch of corner sections The design of masonry and concrete corners was carried out simultaneously and therefore the exact dimensions of the walls and concrete elements was unknown at the start. The above calculations are based on a preliminary calculation, where after there would need to be adjustments in the design to accommodate both structures. The interaction between concrete corner profiles and masonry wall is not taken into consideration. Load transfer in the gable ends The wall sections in the gable follow the same principle as in the façade where the walls are supported in the top by a u profile. The main difference is that there are no roof beams in the gable Page 48 of 65

49 so the u profile has to span from the wall corner to the diaphragm. The deflection in the u profile could be an issue in terms of preventing cracks in the wall sections here. References DS/EN 1990 Basis of structural design. (2010). DS/EN Eurocode 6 ; Design of Masonry Structures. (2006). EC6design.dk. (2013). Olesen, C. J. (2013). Teknisk Ståbi 22.Udgave. Randerstegl. (2013). (2013). Page 49 of 65

50 Design of Concrete Corner Section by SIWA DRAWING K2-300 ANNEX A2.3.2 PRO BP2 -Main Report The concrete corner sections are as mentioned before supporting the whole roof structure by the primary beam. These walls are placed in between the cavity walls in every corner of the building. The walls in the gable directions are also provided with holes for the windows as seen on Figure 62. The loads on the concrete walls will be the same load combination which the primary beams and the connection was dimensioned for. Only the vertical load will be taken from the load combination as we previously mentioned the horizontal forces are taken by steel ties see Figure 63. The external forces are calculated separately and this the wall has to resist. Figure 62 Figure 63 To find the worst case shear in the concrete walls we have used a much more unrealistic method in use. It can be argued for that this method is acceptable as we will find the worst case win in the longitudinal direction and the transversal direction, even though these won t act in the same time. By doing this you have ensured you wall for the worst case situation. The loads applied have taken internal suction and compression into account. The worst case in both direction will be with internal pressure and the forces can be seen in the table above. By taken the worst case load we also use the worst case wall to dimension. If the dimensioning process is verrified than we can use these specification for all the walls. The worst reaction is as Primary beam 4 and this is also the worst wall, see figurs on next pages. Page 50 of 65

51 Figure 64 and Figure 65 below show the plan view of the concrete corner section and an elevation of the chosen wall to dimension. Wall number 4 which is marked on the plan view below has the smallest sections next to the windows to take the forces. Figure 64 Figure 65 The forces which the wall has to resist are the following: 1. Shear from external forces 2. Aksial load from Primary beam 3. Torsion caused by the external forces. Figure 66 indicated the forces acted upon the wall. Wind load from both the longitudinal and transverse direction has to be resisted here. As seen on the figure the forces have an eccentricity regards to the center of the concrete wall. The eccentricity of the wall I of 60 mm. These eccentricities causes a torsional moment which has to be resisted in some way just as shear forces. Before any calculations are made, the center of gravity has to be found which is needed when the stability of the wall is checked. Stability check of both walls have been checked and no problems are found regarding this. The torsional moment in the walls are found based in Figure 66 Betonkonstruktioner efter DS/EN where this says that it is allowed to split the torsional moment into different sections. In our case each wall will be subjected to its own torsional moment and this is what it is chosen to calculate further with. Page 51 of 65

52 To make the calculation more simple, which is will always be the case in real life, the calculation method has been to check if some part of the wall can take the shear and the torsional moment without going into a stringer plan. The marked area in figure 67 is the chosen part of the wall which has to resist the shear and torsion forces. The axial load which the wall is subjected also has an eccentricity. This means in normal conditions the wall has to be dimensioned for the moment which the axial force causes. It is in the calculations estimated that there will be no moment in the wall as the axial wall is placed at the point where the two walls meet. Beside dimensioning the wall for the different load cases it is also important to check the minimum reinforcement. Figure 67 For a more detailed view of the wall please see drawing K2-300 Page 52 of 65

53 Design of Retaining Wall by SIWA Drawing K2-302 ANNEX A2.6.1 As we have no diaphragms in the building to take the reaction from the soil pressure on the basement wall we have to dimension a retaining wall on the outside of the basement wall to take the soil pressure. Figure 68 shows the mentioned situation. As we have a masonry wall on top on the basement wall which needs to transfer wind loads, it is necessary for the basement wall to take some horizontal forces. To prevent this we will make sure that this reaction is taken by the retaining wall by connecting these two with stainless steel. Stainless steel anchor The geotechnical reports which have been provided from GEO shows us that the soil around the building is mainly sand. Therefor it is estimated that we have one kind of soil from top to bottom with the density of 21kN/m 3. The sectional force at the point x on the figure is found based on geotechnical calculations. Figure 68 The dimensioning of the retaining wall are in accordance to Pad foundation compendium version ). The wall has been checked A detailed drawing of the retaining wall can be found in K2-302 that shows the arrangement of the reinforcement in the basement wall. The following has been checked for the retaining wall: 1. Wall dimensioning 2. Finding actions and reactions 3. Moment equilibrium in the structure 4. Finding the moments in the other points 5. Dimensioning of all reinforcement 6. Check for minimum reinforcement 7. Check of compression force in the rigid joint. 8. Checking for anchorage 9. Checking for shear. All dimensioning have been carried out without any problems. Page 53 of 65

54 Proposal for Steel Extension Structure - by MAWS ANNEX A2.2.7 PRO BP2 -Main Report In the North gable end a small framed extension structure is found. This structure is relatively high in comparison with its span and its sole purpose is architectural. The placement of this structure in the gable is seen on the sketch below: Steel Extension Structure Figure 69 - Placement of Steel Extension A proposal for this structure has been completed and can be found in Annex A2.2.7 The process for the proposal of this structure can be summarised by the following: Determine a system for stability Determination of loads on structure including snow, due to the shape it is the only place in the external structure where snow can accumulate. Perform global analysis based on elastic moment distribution Discussion of plastic moment distribution for cross section class 1 profiles. Rough dimensioning of section sizes Connection overview Page 54 of 65

55 It should be noted that this section of the project is simply a proposal, where the general approach to the implementation of the structure discussed. A complete design process would include further investigation. Outcome The structure was investigated for the following load combinations: 1. Wind Leading 1,0 K FI G kj,sup + 1,5 K FI W 2. Self weight Leading 1,2 K FI G kj,sup 3. Snow Leading 1,5 K FI S k + 1,0 K FI G kj,sup + 1,5*ψ*W The worst loading for the frame structure, was determined as transversal wind leading. A rough section size based on elastic analysis is determined to IPE 300, however as the sections are in cross section class 1. The moment distribution and cross section analysis can be performed plastically. The frame structures require two plastic hinges to form before total failure occurs. After formation of the first hinge the moment is redistributed to other parts until two hinges occur. Although a full moment redistribution was not considered, the plastic section modulus is used to reduce the section size to HEB 180. Rectangular hollow sections will be used to stiffen the sections and reduce buckling length around the weak axis of the frame columns. Wind bracing is also placed in the sides of the structure for stability. Figure 70 - Sketch moment curve Further consideration The main connections for the frame structure are given in the annex, however a further proposal was considered, whereby Figure 71 - sketch alternate corner solution the frame was designed to take moments in two directions. The sketch (right), shows the principle of a normal frame corner where the flanges take the normal forces and the corner web acts as a shear field. The idea was to connect a frame also from the other side and to use the web and a welded plate to form a shape in the shear field shown. After investigating this solution, it was decided to use the original suggestion. Page 55 of 65

56 Connection Secondary Beam to Wall by MAWS ANNEX A2.4.2 Annex A2.2.3 Design of secondary beam PRO BP2 -Main Report The connection of the secondary beam to the wall is a connection that has been modelled as a roller support. Meaning that it only supports the beam in vertical direction. The reason for this is that it is imperative that the masonry wall are not subjected to such a large eccentricity. There are many considerations when designing connections with masonry, two of the most important can be summarised below: Appearance Attractive connections often use dowel types connectors where the actual connectors are hidden inside the timber. Construction bolted connections are easier to construct on site than welds for example. For the connection between the secondary beam and wall the connection consists of some prefabricated parts that are welded together and some bolted elements. A sketch can be seen below: Figure 72 - Connection SB / Wall The main principle of the connection is that a plate is bolted to the topside of the timber beams. An arm is welded to the plate and then the web of the arm is supported through a U profile that sits on the top of the wall. It can also be seen that the steel profiles have a connection with the u profile. This is to transfer wind loads on the façade through the U profile and into the roof beams. Page 56 of 65

57 It can also be seen that the HEB profiles are not placed in the same line as the secondary beams. This is due to the placement of the windows in the facade relative to the secondary beams, as the sketch underneath shows; The stiffening steel profiles are placed between the windows. This means that the connection taking the loads into the u profile will take more load than the connections from the u profile to the beam. Figure 73- window beam placement in facade This connection can therefore be split into two main parts: Secondary Beam to wall Wall to U profile Secondary Beam to Wall This part of the connection involves the following steps and calculations; A- T profile Arm B- Connection Plate C- Bolts D- Weld (plate/arm) E- Weld (UNP/arm) Figure 74 - Parts of calculation Page 57 of 65

58 When dimensioning these individual parts, it is necessary to make some assumptions and then adjust dimensions throughout the process. This has been the case with this calculation. The process started and was performed in the order stated on the previous page. A description of the process and the main results is summarized below. Full calculations and detailed sketches can be found in A2.4.2 Forces found in the connection. Figure 75 - Model of Connection As the connection support is a roller, the moment must increase with the distance from the support, hence the moment can be established with the distance e. The force F, has been determined from A The full list of load combinations investigated can be found in the annex, however the dimensioning load case was as follows: Wind Leading W2.f.s Transverse Wind with negative internal pressure 1,5 * W.2.f.s * 1,0 * G This giving a support reaction of 24,9 kn The distance e, from the support to the centre of the action is 405mm, hence a moment of; 24,9 * 0,405 = 10,1 knm at the plate end of the connection. Dimensioning of T profile arm Various dimensions of this profile are investigated to determine a section modulus that can take the moment from the eccentricity. Excel was used to quickly examine different dimensions of the web plate. The flange is present as the connection shall also take a small force in the horizontal Page 58 of 65

59 direction along the wall. This is not investigated in this calculation. The flange will remained at 5mm as this corresponds to the web thickness of the u profile. Connection Plate The connection plate is dimensioned along with the bolts to take the moment in this section similar to a T stub connection with the plane of the timber. This is better described in the annex with sketches. It is ensured that the stresses on the surface of the timber do not exceed the timbers compressive capacity. Bolts M20 bolts are chosen with 37mm washers. The bolts axial and shear resistances are determined in the given timber and the bolts are dimensioned to take the tensile forces determined in the previous step. The initial suggestion was with 4 bolts, however due to a low tensile capacity, this was increased to 8 bolts. The spacing of the bolts in the timber and steel plate are also verified. Weld (arm / plate) Weld around only the web of the arm are used here and the effective stresses in the weld are verified using the procedure given in stålkonstruktioner (9.3). Weld (U profile / arm) This fillet weld like the previous is designed using procedure in stålkonstruktioner and transfers a shear and moment from the action in the u profile. Wall to U Profile The part of the connection that transfers wind to the UNP profile can be seen in figure 26 and essentially consists of 3 parts: Butt weld of plate to the top of HEB section U profile dimensioning The U profile is checked for bending and deflection by a quick hand calculation and is found to be suitable UPE 160. The butt weld has not been calculated but is assumed that a regular butt weld along the length of the HEB web is sufficient. Page 59 of 65

60 Conclusion The dimensioned parts of the connection have been completed and the dimensions are summarised below: T profile dimensions: b1 = 20mm b = 100mm h1= 85mm h2 = 5mm Plate Dimensions: h = 480mm b = 300mm For bolts and weld calculations see A Details as follows: K2 200 K2 200A K2 202 References DS/EN 1990 Basis of structural design. (2010). DS/EN Eurocode 3; Steel Structures. (2007). DS/EN Eurocode 3; Design of Joints. (2007). DS/EN Eurocode 5; Design of Timber Structures. (2009). Page 60 of 65

61 DS/EN Eurocode 6 ; Design of Masonry Structures. (2006). Green, D. W. (n.d.). Mechanical Properties of Wood. Munch-Anderson, J. (2009). Eurocode 5 - Beregninger af forbindelser. NCI regarding EC6. (n.d.). Olesen, C. J. (2013). Teknisk Ståbi 22.Udgave. (2013). Page 61 of 65

62 Connection - Concrete Corner by SIWA DRAWING K ANNEX A2.4.1 As mentioned before, the primary beams which are placed at each corner of the building is connected to concrete corner sections. Figure 77 shows a 3D model of the building, and the marked blue beam is the primary beam. Also the concrete corner section is seen here. On Figure 76 a 3D model of the connection can be seen here. The connection can be split into 3 points: 1. Connection between steel plate and concrete wall 2. Connection between steel element and the two steel plates at ends 3. The connection with the primary beam. The connection which will be dimensioned is as followed: The connection with the concrete wall will be by a 500x340x20 mm steel plate in both direction fastened with bolts. 5 mm welds will be provided for the connection with the steel element The connection with the primary beam will be a bit more special as for the use of in glued bolts. This is made so that the connection with the end of the primary beam can take a moment. Figure 76 Steel element Figure 77 An elastic calculation method is used to find the forces in the bolts. A cross section of the connection can be seen here. It shall be noted that the in glued bolts shall go 500mm into the primary beam. The calculations are found in ANNEX A For a more detailed view of the connection please take a look at drawing K Page 62 of 65

63 Conclusion The tasks set out in the project description have been on the whole completed, however they have also given an insight to the process and problems of designing a building of such structural complexity. There are many cases where some solutions have been slightly contradictory due to changes that were made later in the project phase. The main problems with the project can be summarised as below: From the project outset the difficulty of the building was highly underestimated. In terms of global stability, two main solutions were considered, using both a stiff frame and pinned frame. This was to analyse the effect this would have on the movement of the roof structure. These two solutions have been discussed throughout the projects due to their advantages and disadvantages and as a result some of the structural element calculations have been for different systems. The masonry construction and concrete corners conflict with each other, this is due to a high interaction with each other. As the two areas have been calculated simultaneously the dimensions of the other structures surrounding have been unknown, as is the case with the masonry wall construction and concrete corner profiles. In reality this can be overcome with either a high level of experience from the outset of the project and time to dimension the most important structural elements first. Page 63 of 65

64 Literature List References BDS Fire Technical Guide (DBI vejl.30). (2000). Bekæmpelse, K. (2013). Bent Bonnerup, B. C. (2009 ). Stålkonstruktioner efter DS/EN Udgave. Building Regulations. (2010). Byggeforskningsinstitut, S. (1999). Småhus SBI Anvisning 189. DS/EN 1990 Basis of structural design. (2010). DS/EN Eurocode 1; Actions on Structures. (2007). DS/EN Eurocode 2; Design of Concrete Structures. (2010). DS/EN Eurocode 3; Steel Structures. (2007). DS/EN Eurocode 3; Design of Joints. (2007). DS/EN Eurocode 5; Design of Timber Structures. (2009). DS/EN Eurocode 6 ; Design of Masonry Structures. (2006). EC6design.dk. (2013). Green, D. W. (n.d.). Mechanical Properties of Wood. Guildelines on Building Regulations (SBI version). (2010). J. Rondal, K. W. (1992). Structural Stability of Hollow Sections. Jensen, B. C. (2010). Bygningsberegninger. Jensen, B. C. (2012). Betonkonstruktioner efter DS/EN (2. Udgave). Munch-Anderson, J. (2009). Eurocode 5 - Beregninger af forbindelser. NCI regarding EC6. (n.d.). Olesen, C. J. (2013). Teknisk Ståbi 22.Udgave. Oplysingsråd, T. (2007). Træ of trækonstruktioner 1 (1. udgave). Oplysningsråd, T. (2007). Træ og trækonstruktioner 2 (1. udgave). Ovesen, N. K. (2009). Lærebog i geoteknik (1. udgave). Protection Against Fire In Buildings. translated Eksempelsamling. (2004). Randerstegl. (2013). Society, D. G. (2010). Eksempelsamling til Lærebog i Geoteknik. Page 64 of 65

65 Træinfo.dk. (2013). (2013). (2013). Velfac Windows. Page 65 of 65