CSA S16-09 Design of Steel Structures Canada

Transcription

1 CSA S16-09 Design of Steel Structures Canada Ed Whalen, P.Eng CISC President CSA S CSA Standard S16-09 Standard, Design of Steel Structures. Sets out minimum requirements used by engineers in the design of a broad range of steel structures in Canada. Published by the Canadian Standards Association in September It supersedes S Referenced by the National Building Code of Canada

2 CSA S16-09 Scope and Application 2 SCOPE AND APPLICATION S16-09 provides requirements for: Design Fabrication Erection of steel structures. CSA S16-09 Scope and Application 3 Requirements for steel structures such as: Bridges Offshore structures Cold-formed steel members are found in other CSAStandards. d 2

3 CSA S16-09 Historical Overview 4 Limit States Design Editions Metric Units 2009 S S S S16.1-M S16.1-M S16.1-M78 CSA S16-09 AISC vs CSA S CSA S16-09 Limit States Design only ANSI/AISC Load and Resistance Factor Design (LRFD) Allowable Stress Design (ASD) 3

4 CSA S16-09 Committee Philosophies 6 CSA S16-09 Public safety Steel competiveness Ease of design CSA S16-09 Technical Committee 7 CSA S16-14 (2014) Now on a 5 year cycle Steel racking has been added to this standard Committee is comprised of 30 members - General Interest - Producer Interest - Regulatory Authority - User Interest 6 Universities and 11 professors active 4

5 CSA S Advantages of CSA S16 - Committee fast moving quick to implement changes - Allows Canadian universities/professors to be engaged g Research Committee Member Assists in goal of students choosing structural steel - 5 year cycle - Considered relatively simple approach for designer - References other Canadian Standards as well as American where practical CISC Support to the Standard and Industry 9 CSA Handbook of Steel Construction - CSA S16 Standard - CISC Commentary on CSA S16 - Tables and guidance for Connections and Tension Members - Tables and guidance for Compression Members - Tables and guidance for Flexural Members - Properties and Dimensions - CISC Code of Standard Practice 5

6 CISC Support to the Standard and Industry 10 Other Publications - Limit States Design in Structural Steel - Calcul des charpentes d'acier, Tome I - Calcul l des charpentes d'acier, Tome II - Ductile Design of Steel Structures - Crane-Supporting Steel Structures: Design Guide - Guide to Stability Design Criteria For Metal Structures - Fire Facts for Steel Buildings - Floor Vibrations Due to Human Activity - Hollow Structural Section: Connections and Trusses - A Design Guide - Moment Connections for Seismic Applications - High Strength Bolting for Canadian Engineers - CISC Code of Standard Practice - CISC Guide for Specifying Architecturally Exposed Structural Steel CISC Support to the Standard and Industry 11 Apple, Android, and BB Apps Steel Seismic Systems (SSS10) - assist in identifying permissible structural steel seismic-force-resisting systems (SFRS) in accordance with NBC 2010 and CSA S16-09 based on the Location, Importance Category, Site Class and Building height Lateral Forces (LF10) - LF Wind - computes wind storey forces - LF Seismic - computes seismic storey forces 6

7 CISC Support to the Standard and Industry 12 Courses - CSA S16-09 Changes & Steel Handbook Highlights - Bolting and Welding Fundamentals - Statics ti and Strength th of Materials - Connections I - Connections II - Inspection of Steel Building Structures - Connections for Design Engineers - Single Storey Building Design - Industrial Building Design - Commercial Building Design - Seismic Design of Steel-Framed Buildings - Seismic Connections for Steel-Framed Buildings - Steel Bridges Design, Fabrication, Construction CISC Support to the Standard and Industry 13 Webinars - Budget Pricing of Steel - Architecturally Exposed Structural Steel - Steel Design for Low Seismicity - Fire Protection of Structural Steel - LEED Credits MR

8 CSA S Continual Evolution Selected Changes to CSA S Net Tension Failure T r = φ u A ne F u where: φ u = 0.75 Single-angle Members in Compression - Connected through the same leg 8

9 16 A new clause the shear resistance of tubular and concretefilled tubular members Vr = 0.66 f (A / 2) Fy New Shear resistance for Plastic Members V r = 0.8 φ wdf s where: F s is the shear stress 17 Laterally unsupported beams a) Rational (accurate) method of analysis, or b) Use ω 2 = 1.0 and effective length = 1.2 L for pin-ended beams = 1.4 L for other cases 9

10 18 Laterally unsupported beams - Coefficient for Moment Gradient, ω 2 19 Bearing resistance for bolt holes - φ br = Approx. 20% increase in strength Block Shear T r = φ u [U t A n F u A gv (F y + F u )/2] = [ Tension + Shear contributions ] Bolt bea ring, B r U t = efficiency factor. Value depends on connection type 10

11 Block Shear Flange-Connected Tees U t = 0.9 U t = 1.0 U t = Block Shear Angles connected by one leg and stem connected tees: U t =

12 Block Shear U t = Block Shear su t =

13 24 Multiple Orientation Fillet Welds - New Strength reduction factor M w V r = 0.67 φ A X ( sin 1.5 w w u θ) ) M w M w = 1.0 for single weld orientation 0.85 M w 1.0 for multi-orientation welds longitudinal welds are penalized by the less ductile transverse welds Fillet Welds Strength reduction for multi-orientation welds, M w θ 1 = 90 o θ 2 = 90 o θ 1 = 0 o θ 2 = 0 o M w = M w =

14 Fillet Welds Strength reduction for multi-orientation welds, M w θ 1 = 0 o θ 2 = 90 o M w = Welds and Bolts in Combination Case 1: Bolts + Transverse welds The capacity is the maximum between (a) the bolt and (b) the weld strengths taken separately. The component strengths are not additive. Case 2: Bolts + Longitudinal welds The capacity is the maximum between: (a) Welds Bolts (b) Bolts 14

15 28 Welds and Bolts in Combination Case 3: Bolts + Transverse welds + Longitudinal welds The capacity is the maximum between: (a) Transverse welds Longitudinal welds (b) Longitudinal welds Bolts (c) Bolts only Note: For pretensioned bolts, 25% of the slip resistance is added when only part of the bolt resistance is used. Changes to S16 09 Clause 27 Seismic Design 29 15

16 Gravity Column Splices There is now a minimum shear resistance for gravity columns that are not part of the seismic-forceresisting system (SFRS). V r Σ 0.2 Z F y / h s in both orthogonal directions 30 Seismic Design Traditional construction New Provision 31 16

17 Seismic Design Hollow Structural Sections The minimum probable yield stress for HSS, R y F y, has been increased to 460 MPa (from 385 MPa) to account for their inherently higher characteristic-to- specified yield ratios. 32 Seismic Design Protected Zones Protected zones are areas that undergo large inelastic strains due to seismic loading. They must be indicated on the structural drawings and shop details. Some types of structural or other attachments (e.g. lifting hitches, cladding, etc.) are prohibited within protected zones

18 Seismic Design For moment frames, protected zones are associated with the critical yielding zones around plastic hinges. 34 Seismic Design For braced frames, the entire brace is protected

19 Seismic Design Bucklingrestrained braces 36 Opportunity for South Africa 37 Participate in the CSA S16 Committee Dialogue with CSA on options to modify S16 to needs of SA Possible CISC SAISC Collaboration - Commentary for CSA S16 - Training material, courses and webinars - Technical resources - Design apps - On-Line forums - Other? 19

20 CSA S16-09 Design of Steel Structures Canada Ed Whalen, P.Eng CISC President 20