Shear design for prestressed concrete beams based on compression zone failure mechanism

Abstract

A new shear design method for prestressed concrete beams was developed based on the compression zone failure mechanism. The design method uses a sectional design approach, as used in current design codes. In the method, the concrete shear contribution at each design section is assumed to be mainly provided by intact concrete of the compression zone and is determined based on the material failure criteria of concrete considering the compressive normal stress developed by both the prestressing force and flexural action. Design examples using the proposed method were undertaken and the results were compared with the predictions of current design codes. The proposed method was also applied to existing experimental data. The proposed method showed better strength predictions than various current design codes and predicted the strength variation according to main design parameters with reasonable accuracy.