YS-RCL-BS-03

BENDING, SHEAR AND TORSION

Problem

Design a grade 45 reinforced concrete beam section subjected to 500kNm bending moment, 300kN shear force and 20kNm torsion. The beam section is 300mm x 750mm and cover to reinforcement is 25mm.

Solution

1. Determine the diameter of main and shear reinforcement.
2. Arrange the reinforcement in tension and compression zones, and side where necessary.
3. Calculate the effective depth to tension and compression reinforcement, and total area of reinforcement in those zones.
4. Determine the combined bending moment and torsion resistance provided by longitudinal reinforcement for all cases, referring to cl.3.4.4.4, BS8110-1:1997, and cl.2.4.7 & cl.2.4.9, BS8110-2:1985.
5. Plot the graph of torsion against bending moment.
6. Plot the design bending moment and torsion as a point on the same axis.
7. Determine the link spacing and calculate Asv/Sv.
8. Determine the combined shear force and torsion resistance provided by link for all cases (referring to cl.3.4.5.2, Table 3.7 & Table 3.8, BS8110-1:1997, and cl.2.4.4.1, cl.2.4.5, cl.2.4.6 & cl.2.4.7, BS8110-2:1985).
9. Plot the design shear force and torsion as a point on the same axis.
10. Evaluate the design by inspecting whether the plotted points lie within the envelope of curves.
11. Review the arrangement of reinforcement if the beam section design is inadequate.