Shear Capacity of RC Beams Based on Beam and Arch Actions

Abstract

This study aims to propose a calculation method of shear capacity for RC beams based on the shear resisting mechanisms known as the beam and arch actions. Static four-point bending tests were conducted on 12 RC beams with various stirrup ratio and shear span ratio, and the contribution of each mechanism was calculated based on the strain distribution of tensile steel bars. The contribution of concrete in the beam action at the peak load tends to decrease with higher stirrups amount, while the contribution of the arch action tends to increase with higher stirrups amount and smaller shear span ratio. Based on these results, a new method to calculate the shear capacity of RC beams was proposed. The shear capacity carried by the beam action was obtained from deterministic equations. The shear capacity carried by the arch action was obtained through iteration process, which indirectly takes the compatibility condition into account. From the comparison of a total of 86 experimental and analytical results, the proposed method showed better accuracy to estimate the shear capacity of RC beams with stirrups.