受力筋搭接钢筋混凝土梁受弯性能试验研究

Experimental Study on Flexural Behavior of RC Beams with Lap Splices

为研究钢筋搭接接头对钢筋混凝土梁受弯性能的影响,验证现有钢筋搭接长度修正系数是否能满足混凝土结构设计规范(GB 50010—2010)的正常使用极限状态限值要求,以钢筋搭接长度和搭接百分率为变量,完成了16根两点集中荷载作用下受力钢筋搭接钢筋混凝土简支梁受弯性能试验.对试件的裂缝发展、裂缝宽度、裂缝间距、破坏形态、受弯承载力和跨中挠度等进行了观测.试验结果表明:搭接百分率及钢筋搭接长度对试验梁的承载能力及变形有较大影响,钢筋搭接长度较大的梁试件均能满足承载能力要求;在使用阶段荷载下,试验梁的跨中挠度均满足限值要求,但钢筋搭接长度较小的梁裂缝宽度不满足限值要求.基于试验数据并考虑搭接百分率及钢筋搭接长度两个参数,给出了钢筋搭接梁最大裂缝宽度与钢筋无搭接梁最大裂缝宽度的关系,并提出了钢筋搭接长度修正系数的建议值,以此为基础对我国混凝土结构设计规范及美国ACI 318规范的合理性进行了探讨.

In order to investigate the influence of reinforced bar lap splices on the flexural performance of reinforced concrete beams,and verify whether the existing lap length factor can meet the limit requirements of the serviceability limit state of concrete structure design code(GB50010—2010),taking the lap length and lap percentage as variables,the flexural behavior of 16 reinforced concrete simply supported beams with lap splices under two-point concentrated load was tested.The development of cracks,crack width,crack spacing,failure pattern,flexural bearing capacity,and mid-span deflection of the specimen were observed.The test results show that the lap percentage and lap length have a great influence on the bearing capacity and deformation of the test beams,and the mid-span deflection values of the test beams all meet the limit requirements under the service state load.However,the crack width of the beams with a smaller lap length is difficult to meet.Based on the test data and considering the two parameters of lap percentage and lap length,the relationship between the maximum crack width of beams with lap splices and the maximum crack width of beams without lap splices is given,and the suggested value of the lap length factors is put forward.Based on this,the rationality of the Chinese concrete structure design code and the American ACI 318 code is discussed.