Study On Shear Behaviour Of RC Short Column Retrofitted By Prestressed Steel Jacket

As a new retrofit methodology, prestressed steel jackets(PSJ) can substantially improve the seismic performance of RC columns and show highlighted prospect in the field of structual rehabilitation. This paper aim at developing a calculation method of shear strength for RC short columns retrofitted by PSJ. The following studies are carried out: (1) Nine RC short columns based on substandard shear design are tested under statical loading; (2) The shear mechanism of PSJ is discussed and the shear strength of retrofitted columns are analyzed; (3) Based on the superposition method of shear capacity and the truss-arch model of shear resistant mechianism, two kinds of formula are proposed to calculate the shear strength of RC short column retrofitted by PSJ, respectively.Based on the test results, failure partterns, P-△curve and strain development of PSJ are comprehensively analyzed. The effect of prestressing level(α) and configuration parameter of PSJ(η) on the shear strength of retrofitted columns is especially investigated.Based on the test results, the shear coefficient of PSJ(υs) is analyzed. It is indicated that the shear coefficient of PSJ depends on prestressing level and configuration parameter. According to the superposition method, a formula is suggested to calculate the shear strength, and the calculated results showed good agreement with the test results.According to the analysis of truss-arch model, it is indicated that the shear resistant mechanism of PSJ is similar to transverse reinforcement and that can be described by truss action. Compared theoretical predictions with tset results can concluded that the proposed method can be used to analysis the shear strength.A detailing requirement, design recommendation and construction scheme are suggested for practical application of this new retrofit technique.