RAM Concept Help

Section 3.4.5 Design shear resistance of beams

Included code sections - 3.4.5.1 to 3.4.5.4, 3.4.5.5 (partial), 3.4.5.12

Excluded code sections - 3.4.5.5 (partial), 3.4.5.6 - 3.4.5.11, 3.4.5.13 (considered separately)

See Concrete “Core” Determination for calculation of bv.

vc is calculated per Note 2 of Table 3.8, including the fcu modifier term.

Longitudinal reinforcement designed by Minimum, Service and Strength designers is considered in the determination of As used in the calculation of vc.

100As / bvd is taken as 0.15 minimum, to follow the "=0.15" in table 3.8.

For cross sections with multiple concrete mixes, the minimum fcu is used.

The effective depth is determined by a cracked section analysis using the bending moment and axial force in place at time of the shear being investigated. If all of the reinforcement in the cross section is in compression, then the effective depth is calculated as the distance from the compression-most face to the furthest active reinforcement (in this case 100As / bvd is taken as 0.15).

vc is calculated as the minimum of Equation 6a and Equation 6b, but never less than zero.

fyv is limited to 460 N/mm2 (Amendment 1 and 2) or 500 N/mm2 (Amendment 3).

Links are provided per Table 3.7

Links are only provided in the regions required by calculation, not the whole length of the beam.

Maximum allowed shear stress is the smaller of 5 N/mm2 and 0.8 f c u .

Spacing of links along the span is 0.75 d. The spacing across the span is not considered.

Bent up bars and regions close to supports are not considered.

Bottom loaded beams are not considered.

The anchorage of longitudinal bars is not checked.

Net axial forces are considered if the Consider Net Axial… checkbox is checked.