超高性能混凝土大键齿干接缝受剪性能与承载力计算方法  

Shear performance and bearing capacity calculation method for UHPC dry joints with large-keys

作　　者：王景全[1] 胡玉庆 刘桐旭[1] 李帅[1] 殷惠光[2] WANG Jingquan;HU Yuqing;LIU Tongxu;LI Shuai;YIN Huiguang(Key Laboratory of Concrete and Prestressed Concrete Structure of Ministry of Education,Southeast University,Nanjing 210096,China;School of Civil Engineering,Xuzhou University of Technology,Xuzhou 221018,China)

机构地区：[1]东南大学混凝土及预应力混凝土结构教育部重点实验室,江苏南京210096 [2]徐州工程学院土木工程学院,江苏徐州221018

出　　处：《建筑结构学报》2021年第10期177-185,共9页Journal of Building Structures

基　　金：高铁联合基金项目(U1934205);江苏省高等学校自然科学研究重大项目(18KJA580005);江苏省优秀青年基金(BK20180063);国家自然科学基金项目(51678140);东南大学优秀博士学位论文培育基金项目。

摘　　要：接缝是节段预制拼装超高性能混凝土(UHPC)梁结构中的薄弱部位,其受剪性能不足易引发梁结构的局部剪切破坏,造成结构安全问题。为充分发挥UHPC高强、高韧等优异的力学特性,提出了有无配筋的UHPC大键齿干接缝形式,并通过直剪性能试验分析了大键齿UHPC干接缝的受剪性能。研究结果表明:大键齿UHPC接缝不会发生键齿压碎现象;以大键齿代替多键齿可以提高UHPC接缝的受剪性能;在大键齿UHPC接缝中适当配置抗剪钢筋,可以有效抑制斜裂缝开展,显著提高大键齿干接缝受剪性能。基于试验结果,采用有限元方法进行参数化研究,分析侧向应力、UHPC强度、键齿构型等参数对大键齿干接缝受剪性能的影响。结果表明,对于UHPC大键齿接缝,键齿的深高比设置不宜小于0.167,键齿倾角设置不宜大于45°。基于UHPC材料拉压特性,对美国AASHTO中接缝抗剪强度计算方法进行修正,给出了适用于UHPC键齿干接缝的抗剪强度计算公式。该式计算结果与试验结果的比值为0.89,表明其适用于UHPC键齿干接缝受剪承载力计算。The joint is the important and the weakest component of the precast UHPC segmental bridges(PUSB),of which shear performance has a significant influence on the structural behavior of the PUSB.To make full use of the excellent mechanical properties of UHPC,such as high compressive and tensile strength and high toughness,the reinforced and unreinforced UHPC dry joints with the large-key were proposed in this paper.The results of the direct shear test show that no crushing can be observed,and that the shear performance of the joint with large-keys was improved compared with the joint with small multi-keys,indicating that the large-key is beneficial for avoiding the reduction effect caused by the arrangement of multi-key.Besides,the reinforcement improves the shear performance of large-key UHPC joints.The shear strength of UHPC joints with reinforcement is 12.1%higher than that without reinforcement.In addition to the test,a parametric study was carried out through the nonlinear finite element analysis,and the influence of the confining stress,UHPC strength,and the configuration of large-keys on the shear performance of the large-key UHPC joints was investigated.Based on the results of parametric analysis,the ratio of depth to height of large-key should be greater than 0.167,and the inclination angle of large-key should be smaller than 45°.Moreover,the formula for predicting the shear strength of UHPC joints was proposed based on the relationship of tension and compression of UHPC and the calculation method of AASHTO.The ratio of calculation to test results is 0.89,indicating that the formula is applicable for predicting the shear strength of UHPC joints with large keys.

关 键 词：超高性能混凝土接缝 大键齿 直剪性能试验 受剪性能 承载力 

分 类 号：TU378.203[建筑科学—结构工程] TU311.41