基于拉压杆模型的ECC深梁受剪承载力分析  

Analysis on shear capacity of ECC deep beams based on strut-and-tie model

作　　者：罗敏[1] 胡世翔 潘金龙[1] Luo Min;Hu Shixiang;Pan Jinlong(School of Civil Engineering,Southeast University,Nanjing 211189,China;Institute of Civil Engineering and Intelligent Management,Nanjing Institute of Technology,Nanjing 211167,China)

机构地区：[1]东南大学土木工程学院,南京211189 [2]南京工程学院土木工程与智慧管理研究所,南京211167

出　　处：《东南大学学报（自然科学版）》2021年第4期551-558,共8页Journal of Southeast University：Natural Science Edition

基　　金：国家重点研发计划资助项目(2016YFC0701907);国家自然科学基金资助项目(51778131);江苏省高校自然科学研究面上资助项目(17KJB560006,20KJB580002).

摘　　要：为研究分布筋对ECC深梁破坏模式和受剪承载力的影响,对分布筋配筋率分别为0、0.31%、0.63%的ECC简支深梁进行剪切试验,分析其破坏模式及纵筋和分布筋应变的发展规律.在拉压杆(STM)模型的基础上,根据Mohr-Columb破坏准则推导建立了STM1模型,基于压杆的试验结果建立了STM2模型,并与美国规范ACI318-19中的计算方法进行比较分析.研究结果表明:分布筋配筋率为0和0.31%的ECC深梁均发生压杆破坏,分布筋配筋率为0.63%的ECC深梁发生节点破坏;分布筋配筋率不大于0.31%时,ECC深梁的受剪承载力未随分布筋配筋量的增加而显著增加;与STM2模型及美国规范ACI318-19中的计算方法相比,STM1模型具有明确的力学意义,能考虑ECC材料抗拉性能和分布筋的影响,其计算结果与试验结果吻合良好,可为不同分布筋配筋率下ECC深梁的受剪承载力计算提供依据.To study the influence of web reinforcement on the failure mode and the shear capacity of engineered cementitious composites(ECC)deep beams,three simply supported ECC deep beams with the web reinforcement ratios of 0,0.31%,and 0.63%,respectively,were subjected to shear tests.The failure modes and the strain development of longitudinal reinforcements and web reinforcements were evaluated.On the basis of the strut-and-tie(STM)model,the STM1 model was derived according to the Mohr-Columb failure criterion,and the STM2 model was established based on the test results of the compressed struts.The STM1 model and the STM2 mode were compared with the calculation method in America Code ACI318-19.The results show that the ECC deep beams with the web reinforcement ratios of 0 and 0.31%undergo strut failure,while the ECC deep beam with the web reinforcement ratio of 0.63%undergoes nodal failure.When the web reinforcement ratio is not greater than 0.31%,the shear capacity of the ECC deep beam does not significantly increase with the increase of the amount of web reinforcement.Compared with the STM2 model and the calculation method in America Code ACI318-19,the proposed STM1 model has a clear mechanical significance and can consider the influence of ECC material's tensile properties and web reinforcement.The calculation results of the STM1 model are in good agreement with the experimental ones,thus providing a basis for the calculation of the shear capacity of ECC deep beams with different web reinforcement ratios.

关 键 词：ECC 深梁 受剪承载力 拉压杆模型 分布筋 

分 类 号：TU375.1[建筑科学—结构工程]