Abstract

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Author(s):: QU Wen-jun; LIU Wen-bo; PANG Lei; College of Civil Engineering, Tongji University

Keywords:: mixed stirrup; minimum stirrup ratio; shear capacity; FRP concrete beam; longitudinal reinforcement stiffness

Abstract:: In order to study the minimum stirrup ratio of a mixed reinforcement beam based on the principle of equal durability，the influence factors of the minimum stirrup ratio of the mixed reinforcement component were analyzed, and the calculation formula of the minimum stirrup ratio in various countries was introduced. The shear test of 9 mixed reinforced concrete beams was carried out to verify the failure mode and the strain range of the FRP stirrups under the minimum reinforcement ratio. Based on the formula of shear strength of the mixed reinforced beam and the formula of minimum stirrup ratio in China, the minimum stirrup ratio of the mixed reinforcement beam was theoretically analyzed in the ACI code of the United States, and the formula for calculating the minimum stirrup ratio of the mixed reinforcement members was proposed. The results show that the formula takes into account the effect of the stiffness of the longitudinal reinforcement on the shear bearing capacity of the beam. The simplified formula is simple and clear. It can be used for all stirrup beams and is suitable for engineering applications.