Shear performance of prismatic and tapered beams with corrugated steel webs under external prestressing force

Abstract

This paper analyzes the shear performance of prismatic and tapered beams with corrugated steel webs (CSWs) under different layouts of external prestressing based on finite element (FE) simulations. The results show that when the external prestressing tendon distribution is straight, there is no shear stress in the prismatic beam with CSWs, but there is shear stress in the tapered beam with CSWs. Therefore, it is not generally accurate that only the vertical component of the external prestressing force can induce shear stress when calculating the shear stresses caused by external prestressing in the existing design specifications. In theory, it is proven, for the first time, that the axial force and prestressing bending moment generated by external prestressing will generate additional shear stresses, which will cause the shear stress redistribution in tapered beams with CSWs. However, these two factors were not taken into account in existing design specifications, which resulted in a significant error in predicting the shear stress for tapered beams with CSWs when ignoring the contribution of the axial force and prestressing bending moment. Consequently, a unified analytical formula is proposed for predicting the shear stresses caused by an external prestressing force on the CSW, and this formula can be appropriate for both tapered and prismatic beams with CSWs under both straight and bent external prestressing tendons. In addition, this study quantitatively investigates the ratios of shear stresses in the CSWs induced by the vertical and horizontal components of the external prestressing force, and their corresponding bending moments. Finally, the study reveals the factors affecting the distribution of shear stress on beams with CSWs under external prestressing and proves that using the traditional method to calculate the shear stress neglects the shear capacity of the inclined concrete bottom slab will produce a significant error when applied to tapered cases.