钢 超薄UHPC轻型组合桥面短钢筋连接件#br# 抗剪性能研究

为解决钢-超薄UHPC轻型组合桥面板由于UHPC层过薄而难以采用常规剪力连接件的问题，提出一种新型剪力连接件 短钢筋连接件。通过静力推出试验以及疲劳推出试验对短钢筋连接件的抗剪性能进行初步研究。静力推出试验结果表明：①该试验存在焊缝剪断和UHPC局部破坏(短钢筋拔出)两种破坏模式；②短钢筋连接件承载力随着焊缝长度增加而提高；③短钢筋连接件抗剪承载力高于栓钉，略低于钢筋网焊接件。疲劳推出试验结果表明：80MPa剪应力幅下，3个试件疲劳寿命分别为194.2、271.0、195.8万次，去掉最大值，剩余两者平均疲劳寿命为195万次，略低于规范相应的200万次。通过Miner-Palmgren线性累积损伤理论对不同应力幅下的疲劳次数转化，可得200万次疲劳下的剪应力幅为79.6MPa。仿真结果表明：在纵横向间距200mm×200mm布置方式下，两类疲劳细节(连接件位置与钢顶板位置)均能够满足抗剪疲劳设计要求。文章研究成果可为今后实桥应用提供理论依据。

Research on shear performance of short rebar connectors in #br# steel-ultra thin UHPC lightweight composite deck

It is difficult to apply the structure of steel-ultra thin UHPC lightweight composite deck due to the adoption of the ultra-thin UHPC layer. To solve this problem, an innovative shear connector fabricated from short rebar is proposed. In this work, the shear performance of the short rebar connectors is revealed through static and fatigue tests on push-out specimens. The static tests disclosed that: ① Two failure modes, namely, the break of connector-to-steel deck weld and the localized damage of UHPC, were observed; ② The capacity of the short steel rebar increased with the length of the connector-to-steel deck weld; ③ The shear capacity of the short steel rebar was higher than that of headed stud, but it was lower than that of welded steel mesh. The fatigue tests showed that under a nominal shear stress range of 80 MPa, the fatigue lives of three specimens were 1.942, 2.710, and 1.958 million cycles, respectively. By removing the maximum value, the mean fatigue life of the remaining two specimens was 1.95 million cycles, which is slightly lower than 2 million, a value defined in related design specifications. Based on the fatigue theory of welded structures, the fatigue strength corresponding to a fatigue life of 2 million can be calculated as 79.6 MPa.Furthermore, a detailed finite-element analysis was performed to reveal the response of the proposed short rebar connectors on an orthotropic steel deck bridge. The analysis results indicated that when the spacing of the short rebar connector was 200×200 mm (longitudinal×transverse), both the connector and the connector-to-deck plate weld met the fatigue design requirement. The research results in this work provide theoretical basis for the application of real bridges in the future.