Methods for Calculating Shear Capacity on Oblique Section of Bending Members Strengthened with Enlarged Section

Abstract

We infer that several equations currently used to calculate the bearing capacity of an oblique section of a member strengthened with an enlarged section have several mistakes in the specifications for strengthening the design of highway bridges (JTG/T J22—2008). The shear capacity of the oblique section of a bending member strengthened with an enlarged section could be more accurately and safely calculated using contrastive analysis of relevant design specifications and engineering calculation examples. We particularly challenged the calculation method in which the new stirrups bear the second increased shear based on the proportion of the section area of all web reinforcements. We proposed two calculation methods which can be applied to the general case of unilateral thickening of the member section and the reinforcement of three sides. We also tested an engineering example. The second proposed method, which considered the comprehensive shear capacity of concrete and stirrups, is simple and relatively safe. This method is unified with the design specification of an ordinary bridge component. The proposed method will be adopted in the technical specifications for strengthening of urban bridges which will be enacted soon.