CSA A23.3:24

Preface This is the eighth edition of CSA A23.3, Design of concrete structures. It supersedes the previous editions published in 2019, 2014, 2004, 1994, 1984, 1977 (metric), and 1973 (imperial). This Standard is intended for use in the design of concrete structures for buildings in conjunction with CSA A23.1/CSA A23.2 and CSA A23.4. Changes in this edition include the following: a) new notation and definitions have been added/revised to reflect new and revised requirements; b) new provisions for higher strength reinforcement have been added throughout this Standard; c) clarification concerning the use of this Standard for shotcrete have been provided in Clauses 3, 4, and 5; d) Clause 7 now distinguishes between different types of headed bars; e) Clause 8 contains new specifications for the various grades of reinforcement now permitted by the Standard; f) Clause 9 has an updated expression for the effective moment of inertia used to calculate deflection; g) Clause 10 now distinguishes between two different types of spirals for calculating maximum factored axial load resistance, has a more conservative limit for when slenderness effects may be ignored, and clarifies how slenderness is to be evaluated; h) Clause 11 has revised shear resistance expressions to account for higher strength reinforcement, clarifies the shear reduction at bar cut-off locations, has a revised expression for diagonal crushing due to combined shear and torsion, and has a new requirement for biaxial shear; i) Clause 12 has been revised to reflect provisions for higher strength reinforcement. Provisions to determine the development length of headed bars have been added, and the development length equation for hooked bars has been updated. Provisions for calculating the compression development and splice lengths of deformed bars have been modified. Additional requirements for the mechanical and adhesive anchorage of reinforcement have been introduced and requirements for post-installed reinforcement have been added; j) Clause 13 two-way shear provisions have been updated to include size effect in the expression for shear resistance and additional provisions for headed reinforcement. New shear reinforcement provisions at slab edges have also been included. Slab deflection provisions have been revised to reflect changes made to the deflection provisions in Clause 9; k) Clause 14 has updated requirements for transfer of vertical loads through floors, minimum wall thickness, and slenderness considerations. Clarification is provided on which requirements from Clause 10 need to be applied to walls. Non-bearing walls have been eliminated; l) Clause 16 has been revised to include the following changes: i) stair flights and stair landings are no longer exempt from the requirement to manufacture and erect in accordance with CSA A23.4; ii) a new clause has been introduced limiting horizontal displacement of floor, roof, or wall elements at bearing connections; and iii) Clause 16.5 has been reorganized and updated into general, diaphragm, and vertical element structural integrity clauses, with the more stringent structural integrity provisions now applicable to structures of two or more storeys; m) Clause 21 includes the following changes: i) reinforcement up to 500 MPa may be used for the SFRS and up to 600 MPa may be used for confinement reinforcement; ii) the NBC seismic categories are now used to quantify seismic hazard; iii) the definitions of seismic crosstie and seismic hooks have been moved into the clause; iv) shear magnification has been clarified for partially coupled shear walls; v) lap splice requirements for horizontal wall reinforcement have been clarified; vi) minimum ductility requirements for conventional shear walls are waived when the building is located at a site where the maximum ground displacement is small and shear walls are flexible; vii) connection requirements for precast concrete shear walls have been clarified; and viii) new clauses provide guidance on how to apply seismic performance requirements in the NBC for certain categories of buildings; and n) Annex D has received significant revision and now includes provisions for screw anchors and shear lugs. Beneficial calculations for interaction between tension and shear and overturning forces have been introduced. Reliability factors have been revised. Inspection requirements have been clarified and expanded to incorporate post-installed reinforcing bars. This Standard was prepared by the Technical Committee on Reinforced Concrete Design, under the jurisdiction of the Strategic Steering Committee on Construction and Civil Infrastructure, and has been formally approved by the Technical Committee. This Standard has been developed in compliance with StandardDetails Council of Canada requirements for National StandardDetails of Canada. It has been published as a National Standard of Canada by CSA Group. 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; and b) plain concrete elements. Notes: 1) For structures such as blast-resistant structures, tanks, reservoirs, swimming pools, bins, silos, towers, and chimneys, users of this Standard should also refer to applicable codes, StandardDetails, or guidelines for additional requirements 2) Special requirements for parking structures are specified in 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). Note: Information on the fire resistance of concrete elements can be found in Appendix D of the National Building Code of Canada. 1.3 Alternative design procedures Designs that use procedures 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 Shells and folded plates Design requirements for shells and folded plates can be found in Annex E. 1.5 Terminology In this Standard, "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; and "may" is used to express an option or that which is permissible within the limits of the Standard. 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. 1.6 Units of measurement Equations appearing in this Standard are compatible with the following units: a) area: mm 2 (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 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.