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D. CAN/CSA-A23.3-10 Column Design Principles

The CAN/CSA-A23.3-10 Column Design Brief is for prismatic, solid rectangular, or circular shaped members. Members may be built up from multiple elements, but only the member end moments are considered. Therefore, only single height columns are recommended.

Design Principles

Columns are designed for axial force and biaxial end moments, as well as biaxial shear. Provided reinforcement is calculated by the program based on the forces generated from the analysis model and the code clauses outlined below.

The main reinforcing bars may be modified to allow for other bars passing through the section and then rechecked to ensure that the design requirements are satisfied.

All selected load combinations are used to calculate the required reinforcement. The combination which produces the maximum required reinforcement area is called the "Guiding Load Case", and the bar arrangement is chosen based on that combination. The detailed printout of the design calculations is for that combination.

Code Clauses Implemented

The requirements of CAN/CSA-A23.3-10 utilized in the design module are as follows:


  • 8.4.2-3
  • 8.5.1 – Design calculations are based on the specified yield strength of reinforcement. A warning is reported if the specified yield strength is greater than 500 MPa.
  • – The modulus of elasticity of concrete is calculated using equation 8-1 in the code. The specified density, γc , is used in the equation but if it is outside of the range 1,500 to 2,500 kg/m3, a warning is reported. Altern
  • 8.6.4-5 – The modulus of rupture, fr , is calculated use equation 8-3.
  • 10.1.3
  • 10.1.5-6

Minimum Reinforcement

  • – Bundled bars are not considered.
  • 10.9.1-4 – The minimum reinforcement for columns is 0.01×Ag . If reinforcement exceeds 0.04×Ag , a warning is reported. If reinforcement exceeds 0.08×Ag , a failure is reported. Ag is the gross cross sectional area of the column. A minimum of 4 or 6 bars is required for rectangular or round columns, respectively (for irregularly shaped columns, no design check is performed).
  • 10.10.5

Ultimate Limit State

  • 10.1.2 - The strain in the reinforcement and concrete are assumed to be directly proportional to the distance from the neutral axis. For deep flexural members, the design is performed using the plane sections remain plane assumption, but a warning is reported.
  • 10.1.5 – The tensile strength of concrete is neglected.
  • 10.9.4
  • 10.10.4-5
  • 11.2.10
  • 11.3.1
  • 11.3.3-4

Development Length

  • 12.1.2
  • 12.2.1-2
  • 12.2.4-5
  • 12.3.1-3
  • 12.5.1-3