Study On Shear Capacity And Deformation Of Concrete Members Confined With High-strength Stirrup

It is very effective that concrete member is confined with high-strength stirrup to improve capacity and deformation performance of the members. This paper mainly studies the shear strength and deformation performance of the members by experiments and theoretical analysis.Based on the section mechanical analysis of tested beams, a model is developed to predict the shear strength of reinforced concrete beams with and without web reinforcement. It is assumed that the shear strength of concrete beams is primarily provided by concrete in the compressive zone on the top of critical section.In this paper, 211 non-web reinforcement beams and 107 concrete members confined with high-strength stirrup were collected to test datum. The factors to affect shear strength of concrete including shear span ratio, axial compression ratio, concrete strength, ratio of longitude bar, ratio of stirrup and so on were analyzed. Based on regression analysis of these 107 beams and columns, the formulas used to calculate the shear strength of members are proposed. The formulas take into account concrete strength, span-to-depth ratio, axial compression ratio, longitudinally reinforcement ratio and the average confining stress. The testing results are compared with failure shear strength calculated by the Code for design of concrete structures 'GB50010-2002' and the Code for design guide of concrete structures. The results indicated that the calculation of Chinese code is high and insecurity, the calculation of Japanese code is low and conservative while the calculation of regression formula lies between the two. It can be used to calculate the shear capacity of the high-strength concrete beam stirrups.The concrete columns confined with the high-strength tirrup showed good plastic and greater efficiency in fixing on the construction site. A formula on calculating the limiting rotation angle was proposed based on the test data collected. The results from the proposed formula conformed fine to the experiment data.