D1.F.4.3 Shear and Torsion Design
In the absence of torsion, the required shear bar density at cross section at each cross section will initially be calculated for shear along both the local Z and Y axes. Based on these required shear densities, the program will divide the member into one or more shear zones such that each zone (between the start and end cross sections) will require the same shear density. Once the shear zones have been identified, transverse bar links will be provided based on the bar size specified using the MINSEC parameter. In order to meet the required density demand, the program will start with the minimum number of legs and calculate the most optimum spacing for the transverse links. If the minimum / maximum spacing criteria cannot be met during this process, additional legs will be added and the spacings adjusted to optimize the design. Note that the program will use the same bar size for links to cater for shear along both the X a nd Z directions to maintain a practical design.
Note that the program will use the same bar size for all transverse bars to cater for shear requirements in both axes to maintain a practical design .
If the beam is also subject to torsional forces (MX), both the longitudinal steel as well the transverse steel will be designed to cater for the applied torsion, in addition to any longitudinal or transverse steel that would have been required for the bending/ shear effects. The torsion force increases the demand in the transverse due to pure shear and longitudinal direction due to warping effects.
See section F.7 for the clauses considered for shear and torsion design.