PBL连接件在长期荷载作用下的试验研究

EXPERIMENTAL RESEARCH ON PERFOBOND SHEAR CONNECTORS UNDER LONG-TERM LOADING

为了研究PBL连接件在长期荷载作用下的受力性能,对6个PBL连接件试件进行了6个月的长期加载试验及极限承载力破坏试验,考虑的影响参数为钢板开孔直径、厚度和孔洞个数。试验考察了试件变形发展过程及破坏形态,得到了试件荷载-滑移曲线以及荷载-横向贯通钢筋应变曲线,并建立了钢梁与混凝土板相对滑移、横向贯通钢筋和孔洞周边应力与加载时间关系曲线;最后,在试验的基础上,对比总结了长期荷载和短期荷载作用对PBL连接件力学性能的影响。研究结果表明：增加开孔钢板直径、厚度和孔洞个数可以有效提高PBL连接件抗剪刚度,减小其相对滑移;与短期荷载作用下的试验结果相比,长期荷载作用下PBL连接件试件的抗剪刚度下降了16%~30%,但其破坏形态、荷载-横向贯通钢筋应变曲线、荷载-滑移曲线变化特点基本相同,且其极限抗剪承载力无显著差异。

In order to investigate the mechanical properties of perfobond shear connectors under long-term loading,six PBL specimens were tested under 6-month long-term loading and their ultimate bearing capacity were also investigated. The parameters studied in the paper consisted of the steel plate thickness,the opening diameter as well as the opening number. The experimental programme examined the deformation process and the failure mode of these specimens. The load-slip curves and the load-strain of transverse rebar relationship were studied. The relationship curves of loading time versus relative slip between the steel beam and the concrete slab,transverse rebar strain,von Mises stress of steel plated were obtained. Finally,the effects of short-term loading and long-term loading on the mechanical properties of perfobond shear connectors were summarized and discussed. The results showed that with the increase of the steel plate thickness,the opening diameter and the opening number could effectively improve the shear stiffness of the perfobond shear connectors and reduce the relative slip. Compared with the test results under the shortterm loading,the shear stiffness of the PBL connector was reduced by 16% ~ 30% under the long-term loading.However,the failure modes of the specimens,the load-strain of transverse rebar relationship,the characteristics of the load-slip curves were basically similar,and the ultimate shear capacity had no significant difference.