SHEAR RESISTANCE OF BEAMS WITH SHALLOW-ANGLE BENT-UP BARS

Researchers in Germany have proposed 'adjusting' the reinforcement of beams critical in shear to follow the bending moment diagram. This wou ld result in a significant reduction in the effective shear force. Tes ts have confirmed their assumptions, although no theoretical model has been developed for the analysis or optimization of the proposed reinf orcement layout. This paper describes a theoretical and experimental s tudy of beams with and without shear reinforcement conducted at Queen' s University Belfast. The truss analogy was used to analyse beams with standard and 'adjusted' reinforcement. Reinforcement layouts based on the elastic stress distribution in a beam were developed. Five beams with standard reinforcement and with layouts based on this analysis we re built and tested. The beam with an adjusted reinforcement closest t o the elastic stress distribution exceeded the load capacity of the be am with standard reinforcement, while experiencing significantly small er deflections and less cracking, The experimental results compared we ll with those obtained using the theoretical models.