Canadian Standards Association Design of concrete structures Preface This is the fifth edition of CSA A23. 3, Design of concrete structures. It supersedes the previous editions blished in 1994, 1984, 1977(metric)and 1973(imperial), and 1959 This Standard is intended for use in the design of concrete structures for buildings in conjunction with CSA A23. 1-04/A23.2-04, Concrete materials and methods of concrete construction/Methods of test and standard practices for concrete, and CSA A23. 4, Precast concrete-Materials and construction(under Changes in this edition include the follor (a) This Standard is now based on the load factors and load combinations specified in the National Building Code of Canada, 2005(see Annex C) (b)Clause 2.2 contains new definitions for different types of walls; these depend on the level of axial load and the primary loading on the wall (c) In Clause 8.4.2, the resistance factor for concrete, o has been increased from 0.60 to 0.65 (d) Clause 10 on flexure and axial loads contains a revised alternative expression for calculating the flexural stiffness, El, for slenderness effects (e)Clause 11 on shear and torsion contains new design provisions for members such as slabs, footings, joists, and wide shallow beams. Clause 11.3.6.3 provides a new, simplified method for shear design Clause 11.3.6.4 contains revised design provisions for the general method. These revised design provisions are based on the modified compression field theory Clause 13 on two-way slab systems has been revised to provide different distribution factors for factored moments in column strips. New requirements for slab band construction are also specified (g) Clause 14 contains new provisions for reinforcement details for walls, including requirements for concentrated reinforcement and ties for vertical reinforcement. a new clause(clause 14. 4)on the structural design of shear walls has been added. It includes requirements for compression flanges for assemblies of interconnected walls (h )Clause 15 on foundations includes new clauses on the design requirements for pile caps and piles () In Clause 16 on precast concrete, the resistance factor for concrete, pc, has been increased from 0.65 to 0.70 for the design of elements produced in CSA-certified manufacturing plants o Clause 18 on prestressed concrete has a modified expression for the stress in unbonded prestressing tendons at factored resistance (k) Clause 21 on special provisions for seismic design specifies requirements that conform to the new categories for seismic force resisting systems in the National Building Code of Canada, 2005. Provisions for determining member stiffnesses have been added. The requirements for checking that the columns are stronger than the beams have been changed for the design of ductile frames and frames with moderate ductility. In Clause 21.4.4, the requirements for confinement reinforcement for columns have been changed to include the effects of axial load level as well as the arrangement of transverse reinforcement and longitudinal bars. Maximum spacing limits for transverse reinforcement in columns of ductile frames have been changed. New ductility requirements have been added in Clause 21.6 for individual walls, coupled walls, partially coupled walls, and coupling beams. In Clause 21.6.9 on shear strength of ductile walls, the method for determining the factored shear resistance has been changed. New requirements for the design of squat walls have been added in Clause 21.7.4. A new clause(Clause 21.8)on conventional construction (Rd= 1.5) has been added Clause 21.9 provides new requirements for ductile moment resisting frames, ductile shear walls, and moderately ductile shear walls constructed using precast concrete. New requirements for the design of structural diaphragms have been added in Clause 21.10 Clause 21 11 provides new requirements for foundations, including footings, foundation mats, pile caps, grade beams, slabs on grade, piles, piers, and caissons. Revised requirements for the design of frame members not considered part of the seismic force resisting system are specified in Clause 21.12 Clause 22 on plain concrete contains a new clause( Clause 22. 8)on the design of deep foundations December 2004
© Canadian Standards Association Design of concrete structures December 2004 xvii Preface This is the fifth edition of CSA A23.3, Design of concrete structures. It supersedes the previous editions published in 1994, 1984, 1977 (metric) and 1973 (imperial), and 1959. This Standard is intended for use in the design of concrete structures for buildings in conjunction with CSA A23.1-04/A23.2-04, Concrete materials and methods of concrete construction/Methods of test and standard practices for concrete, and CSA A23.4, Precast concrete — Materials and construction (under preparation). Changes in this edition include the following: (a) This Standard is now based on the load factors and load combinations specified in the National Building Code of Canada, 2005 (see Annex C). (b) Clause 2.2 contains new definitions for different types of walls; these depend on the level of axial load and the primary loading on the wall. (c) In Clause 8.4.2, the resistance factor for concrete, φc , has been increased from 0.60 to 0.65. (d) Clause 10 on flexure and axial loads contains a revised alternative expression for calculating the flexural stiffness, EI, for slenderness effects. (e) Clause 11 on shear and torsion contains new design provisions for members such as slabs, footings, joists, and wide shallow beams. Clause 11.3.6.3 provides a new, simplified method for shear design. Clause 11.3.6.4 contains revised design provisions for the general method. These revised design provisions are based on the modified compression field theory. (f) Clause 13 on two-way slab systems has been revised to provide different distribution factors for factored moments in column strips. New requirements for slab band construction are also specified. (g) Clause 14 contains new provisions for reinforcement details for walls, including requirements for concentrated reinforcement and ties for vertical reinforcement. A new clause (Clause 14.4) on the structural design of shear walls has been added. It includes requirements for compression flanges for assemblies of interconnected walls. (h) Clause 15 on foundations includes new clauses on the design requirements for pile caps and piles. (i) In Clause 16 on precast concrete, the resistance factor for concrete, φc , has been increased from 0.65 to 0.70 for the design of elements produced in CSA-certified manufacturing plants. (j) Clause 18 on prestressed concrete has a modified expression for the stress in unbonded prestressing tendons at factored resistance. (k) Clause 21 on special provisions for seismic design specifies requirements that conform to the new categories for seismic force resisting systems in the National Building Code of Canada, 2005. Provisions for determining member stiffnesses have been added. The requirements for checking that the columns are stronger than the beams have been changed for the design of ductile frames and frames with moderate ductility. In Clause 21.4.4, the requirements for confinement reinforcement for columns have been changed to include the effects of axial load level as well as the arrangement of transverse reinforcement and longitudinal bars. Maximum spacing limits for transverse reinforcement in columns of ductile frames have been changed. New ductility requirements have been added in Clause 21.6 for individual walls, coupled walls, partially coupled walls, and coupling beams. In Clause 21.6.9 on shear strength of ductile walls, the method for determining the factored shear resistance has been changed. New requirements for the design of squat walls have been added in Clause 21.7.4. A new clause (Clause 21.8) on conventional construction (Rd = 1.5) has been added. Clause 21.9 provides new requirements for ductile moment resisting frames, ductile shear walls, and moderately ductile shear walls constructed using precast concrete. New requirements for the design of structural diaphragms have been added in Clause 21.10. Clause 21.11 provides new requirements for foundations, including footings, foundation mats, pile caps, grade beams, slabs on grade, piles, piers, and caissons. Revised requirements for the design of frame members not considered part of the seismic force resisting system are specified in Clause 21.12. (l) Clause 22 on plain concrete contains a new clause (Clause 22.8) on the design of deep foundations
A23.3-04 o Canadian Standards associatid (m) There is a new Annex d on anchorage based on the requirements specified in Appendix d of ACI (American Concrete Institute)318M-02/318RM-02, Building Code Requirements for Structural Concrete and Commentary. Annex d deals with anchors cast into the concrete or post-installed into hardened concrete. It covers anchors used to transmit applied loads, including straight bolts, hooked bol headed studs, expansion anchors, undercut anchors, and inserts This Standard was prepared by the Technical Committee on Reinforced Concrete Design, under the jurisdiction of the Strategic Steering Committee on Structures(Design), and has been formally approved y the Technical Committee. It will be submitted to the Standards Council of Canada for approval as a National Standard of canada December 2004 Notes: (1)Use of the singular does not exclude the plural (and vice versa)when the sense allows (2) Although the intended primary application of this Standard is stated in its Scope, it is important to note that it remains the responsibility of the users of the Standard to judge its suitability for their particular purpose ()This publication was developed by consensus, which is defined by CSa Policy governing standardization-Code of good practice for standardization as"substantial agreement. Consensus implies much more than a simple majority but not necessarily unanimity". It is consistent with this definition that a member may be included in the Technical Committee list and yet not be in full agreement with all clauses of this publication (4) CSA Standards are subject to periodic review, and suggestions for their improvement will be referred to the appropriate committe (s)All enquiries regarding this Standard, including requests for interpretation, should be addressed to Canadian Standards (a)define riate include an illustrative sketch (c) be phrased where possible to permit a specific "yes"or"no"answer. Committee interpretations are processed in accordance with the CSA Directives and guidelines governing standardization and are published in CSA's periodical Info Update, which is available on the CSa Web site at Www. Csa ca December 2004
A23.3-04 © Canadian Standards Association xviii December 2004 (m) There is a new Annex D on anchorage based on the requirements specified in Appendix D of ACI (American Concrete Institute) 318M-02/318RM-02, Building Code Requirements for Structural Concrete and Commentary. Annex D deals with anchors cast into the concrete or post-installed into hardened concrete. It covers anchors used to transmit applied loads, including straight bolts, hooked bolts, headed studs, expansion anchors, undercut anchors, and inserts. This Standard was prepared by the Technical Committee on Reinforced Concrete Design, under the jurisdiction of the Strategic Steering Committee on Structures (Design), and has been formally approved by the Technical Committee. It will be submitted to the Standards Council of Canada for approval as a National Standard of Canada. December 2004 Notes: (1) Use of the singular does not exclude the plural (and vice versa) when the sense allows. (2) Although the intended primary application of this Standard is stated in its Scope, it is important to note that it remains the responsibility of the users of the Standard to judge its suitability for their particular purpose. (3) This publication was developed by consensus, which is defined by CSA Policy governing standardization — Code of good practice for standardization as “substantial agreement. Consensus implies much more than a simple majority, but not necessarily unanimity”. It is consistent with this definition that a member may be included in the Technical Committee list and yet not be in full agreement with all clauses of this publication. (4) CSA Standards are subject to periodic review, and suggestions for their improvement will be referred to the appropriate committee. (5) All enquiries regarding this Standard, including requests for interpretation, should be addressed to Canadian Standards Association, 5060 Spectrum Way, Suite 100, Mississauga, Ontario, Canada L4W 5N6. Requests for interpretation should (a) define the problem, making reference to the specific clause, and, where appropriate, include an illustrative sketch; (b) provide an explanation of circumstances surrounding the actual field condition; and (c) be phrased where possible to permit a specific “yes” or “no” answer. Committee interpretations are processed in accordance with the CSA Directives and guidelines governing standardization and are published in CSA’s periodical Info Update, which is available on the CSA Web site at www.csa.ca
Canadian Standards Association Design of concrete structures A23.3-04 Design of concrete structures ope 1.1 General This Standard specifies requirements, in accordance with the National Building Code of Canada, for the design and strength evaluation of (a) structures of reinforced and prestressed concrete (b) plain concrete elements; and (c) special structures such as parking structures, arches, tanks, reservoirs, bins and silos, towers, water towers, blast-resistant structures, and chimneys Note: Special requirements for parking structures are specified in CAN/CSA-5413 1.2 Fire resistance This Standard requires designs to be carried out in accordance with the fire resistance requirements of the applicable building code(see Clause 8.1.2) 1.3 Alternative design procedures Designs that use procedures which are not covered by this Standard but are carried out by a person qualified in the methods applied and provide a level of safety and performance equivalent to designs complying with this Standard are acceptable if carried out by one of the following methods: (a) analysis based on generally established theory; (b) evaluation of a full-scale structure or a prototype by a loading test; or (c studies of model analogues 1.4 Terminology In CSA Standards, shall"is used to express a requirement, i.e. a provision that the user is obliged to satisfy in order to comply with the standard; "should"is used to express a recommendation or that which is advised but not required; "may"is used to express an option or that which is permissible within the limits of the standard; and"can"is used to express possibility or capability. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory)or informative(non-mandatory) to define their application 1. 5 Units of measurement Equations appearing in this Standard are compatible with the following units (a)area mm (b force: N(newtons); (c) length: mm(millimetres); (d) moment: Nmm(newton millimetres); and (e) stress: MPa(megapascals). Whenever the square root of the concrete strength is determined the concrete strength and the square oot of the concrete strength are both expressed in megapascals Other dimensionally consistent combinations of units may be used, provided that appropriate adjustments are made to constants in non-homogeneous equations Note: Some examples of non-homogeneous equations are found in Clauses 12.2.2 and 12.8 December 2004
© Canadian Standards Association Design of concrete structures December 2004 1 A23.3-04 Design of concrete structures 1 Scope 1.1 General This Standard specifies requirements, in accordance with the National Building Code of Canada, for the design and strength evaluation of (a) structures of reinforced and prestressed concrete; (b) plain concrete elements; and (c) special structures such as parking structures, arches, tanks, reservoirs, bins and silos, towers, water towers, blast-resistant structures, and chimneys. Note: Special requirements for parking structures are specified in CAN/CSA-S413. 1.2 Fire resistance This Standard requires designs to be carried out in accordance with the fire resistance requirements of the applicable building code (see Clause 8.1.2). 1.3 Alternative design procedures Designs that use procedures which are not covered by this Standard but are carried out by a person qualified in the methods applied and provide a level of safety and performance equivalent to designs complying with this Standard are acceptable if carried out by one of the following methods: (a) analysis based on generally established theory; (b) evaluation of a full-scale structure or a prototype by a loading test; or (c) studies of model analogues. 1.4 Terminology In CSA Standards, “shall” is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; “should” is used to express a recommendation or that which is advised but not required; “may” is used to express an option or that which is permissible within the limits of the standard; and “can” is used to express possibility or capability. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application. 1.5 Units of measurement Equations appearing in this Standard are compatible with the following units: (a) area: mm2 (square millimetres); (b) force: N (newtons); (c) length: mm (millimetres); (d) moment: N•mm (newton millimetres); and (e) stress: MPa (megapascals). Whenever the square root of the concrete strength is determined, the concrete strength and the square root of the concrete strength are both expressed in megapascals. Other dimensionally consistent combinations of units may be used, provided that appropriate adjustments are made to constants in non-homogeneous equations. Note: Some examples of non-homogeneous equations are found in Clauses 12.2.2 and 12.8
A23.3-04 e Canadian standards association 2 Reference publications, definitions, symbols, and standard notation and calculations 2.1 Reference publications This Standard refers to the following publications, and where such reference is made, it shall be to the edition listed below, including all amendments published thereto CSA(Canadian Standards Association) A23.1-04/A232-04 Concrete materials and methods of concrete construction/Methods of test and standard practices for concrete Note: Excerpts from this Standard are presented in Annex A A23. 4(under preparation) Precast concrete- Materials and construction CAN/CSA-G30. 18-M92(R2002 Billet-steel bars for concrete reinforcement G40.20-04G40.21-04 General requirements for rolled or welded structural quality steel/Structural quality steel CAN/CSA-S16-01 Limit states design of steel structures CAN/CSA-S413-94(R2000) Parking structures W59-03 Welded steel construction(metal arc welding) W186M1990(R2002) melding of reinforcing bars in reinforced concrete construction ACI(American Concrete Institute) 18M02/318RM-02 Metric Building Code Requirements for Structural Concrete and Commentary 336.3R93 Design and Construction of Drilled Piers 355.2-04/355.2R-04 Qualification of Post-Installed Mechanical Anchors in Concrete and Commentary 360R-97 Design of Slabs on Grade T1.101/T1.1R01 Acceptance Criteria for Moment Frames Based on Structural Testing ASTM International(American Society for Testing and Materials) A185-02 Standard Specification for Steel Welded Wire reinforcement, Plain, for Concrete December 2004
A23.3-04 © Canadian Standards Association 2 December 2004 2 Reference publications, definitions, symbols, and standard notation and calculations 2.1 Reference publications This Standard refers to the following publications, and where such reference is made, it shall be to the edition listed below, including all amendments published thereto. CSA (Canadian Standards Association) A23.1-04/A23.2-04 Concrete materials and methods of concrete construction/Methods of test and standard practices for concrete Note: Excerpts from this Standard are presented in Annex A. A23.4 (under preparation) Precast concrete — Materials and construction CAN/CSA-G30.18-M92 (R2002) Billet-steel bars for concrete reinforcement G40.20-04/G40.21-04 General requirements for rolled or welded structural quality steel/Structural quality steel CAN/CSA-S16-01 Limit states design of steel structures CAN/CSA-S413-94 (R2000) Parking structures W59-03 Welded steel construction (metal arc welding) W186-M1990 (R2002) Welding of reinforcing bars in reinforced concrete construction ACI (American Concrete Institute) 318M-02/318RM-02 Metric Building Code Requirements for Structural Concrete and Commentary 336.3R-93 Design and Construction of Drilled Piers 355.2-04/355.2R-04 Qualification of Post-Installed Mechanical Anchors in Concrete and Commentary 360R-97 Design of Slabs on Grade T1.1-01/T1.1R-01 Acceptance Criteria for Moment Frames Based on Structural Testing ASTM International (American Society for Testing and Materials) A 185-02 Standard Specification for Steel Welded Wire Reinforcement, Plain, for Concrete
Canadian Standards Association gn of concrete structures A307-04 Standard specification for Carbon Steel Bolts and Studs, 60 000 PSI Tensile Strength A416/A416M-02 Standard specification for Steel Strand, Uncoated Seven-Wire for Prestressed Concrete A421/A421M-02 Standard Specification for Uncoated Stress-Relieved Steel Wire for Prestressed Concrete A496-02 Standard specification for Steel Wire, Deformed, for Concrete Reinforcement A497A497M-02 Standard specification for Steel Welded Wire Reinforcement, Deformed, for Concrete A722A722M-98(2003) Standard Specification for Uncoated High-Strength Steel Bar for Prestressing Concrete C330-04 Standard Specification for Lightweight Aggregates for Structural Concrete AWS(American Welding Society) D1.1/D1.1M:2004 Structural Welding Code- Steel NRCC(National Research Council Canada) National Building Code of Canada, 2005 User's Guide- NBC 2005: Structural Commentaries(Part 4) Other publications ACI-ASCE Committee 550. 1993. Design recommendations for precast concrete structures. ACI structural journal. 90: 115-121 Canadian Precast/Prestressed Concrete Institute. 2005. Design manual: Precast and prestressed concrete 4th ed. Ottawa: Canadian Precast/Prestressed Concrete Institute. Cement Association of Canada. 2005. Concrete design handbook. 3rd ed. Ottawa: Cement Association of Canada Precast/Prestressed Concrete Institute. 1999. PCI design handbook: Precast and prestressed concrete. Sth ed Chicago: Precast/Prestressed Concrete Institute 2.2 Definitions The following definitions apply in this Standard Auxiliary member-a rib or edge beam that serves to strengthen, stiffen, or support the shell. Auxiliary members usually act jointly with the shell Base(of a structure)-the level at which earthquake motions are assumed to be imparted to a structure This level does not necessarily coincide with the ground level Beam-an element subjected primarily to loads and forces producing flexure Bell- an enlargement at the bottom of a pre-drilled cast-in-place concrete pile December 2004
© Canadian Standards Association Design of concrete structures December 2004 3 A 307-04 Standard Specification for Carbon Steel Bolts and Studs, 60 000 PSI Tensile Strength A 416/A 416M-02 Standard Specification for Steel Strand, Uncoated Seven-Wire for Prestressed Concrete A 421/A 421M-02 Standard Specification for Uncoated Stress-Relieved Steel Wire for Prestressed Concrete A 496-02 Standard Specification for Steel Wire, Deformed, for Concrete Reinforcement A 497/A 497M-02 Standard Specification for Steel Welded Wire Reinforcement, Deformed, for Concrete A 722/A 722M-98 (2003) Standard Specification for Uncoated High-Strength Steel Bar for Prestressing Concrete C 330-04 Standard Specification for Lightweight Aggregates for Structural Concrete AWS (American Welding Society) D1.1/D1.1M:2004 Structural Welding Code — Steel NRCC (National Research Council Canada) National Building Code of Canada, 2005 User’s Guide — NBC 2005: Structural Commentaries (Part 4) Other publications ACI-ASCE Committee 550. 1993. Design recommendations for precast concrete structures. ACI structural journal. 90:115–121. Canadian Precast/Prestressed Concrete Institute. 2005. Design manual: Precast and prestressed concrete. 4th ed. Ottawa: Canadian Precast/Prestressed Concrete Institute. Cement Association of Canada. 2005. Concrete design handbook. 3rd ed. Ottawa: Cement Association of Canada. Precast/Prestressed Concrete Institute. 1999. PCI design handbook: Precast and prestressed concrete. 5th ed. Chicago: Precast/Prestressed Concrete Institute. 2.2 Definitions The following definitions apply in this Standard: Auxiliary member — a rib or edge beam that serves to strengthen, stiffen, or support the shell. Auxiliary members usually act jointly with the shell. Base (of a structure) — the level at which earthquake motions are assumed to be imparted to a structure. This level does not necessarily coincide with the ground level. Beam — an element subjected primarily to loads and forces producing flexure. Bell — an enlargement at the bottom of a pre-drilled cast-in-place concrete pile