带翼缘板嵌入式连接件抗剪性能提升试验研究

Experimental Study on Shear Performance Improvement of Embedded Connector with Flange

为防止波纹钢腹板PC箱梁桥带翼缘板嵌入式连接件翼缘板过早失稳导致失去抗剪能力,在翼缘板宽厚比较大处焊接栓钉。设计制作7组足尺试件进行推出试验,分析栓钉强化的带翼缘板嵌入式连接件在剪力作用下的破坏形态和荷载滑移性能,以及翼缘板宽厚比、腹板嵌入深度、翼缘板栓钉、腹板厚度和接合钢筋直径对抗剪性能的影响,并验证嵌入式连接件极限承载力计算公式适用性。结果表明:栓钉强化的带翼缘板嵌入式连接件试件破坏模式为混凝土劈裂,荷载~滑移曲线分为弹性阶段、屈服阶段、破坏阶段。在翼缘板宽厚比较大处焊接栓钉,阻止了翼缘板失稳,抗剪承载力得到显著提高;翼缘板宽厚比、腹板嵌入深度对栓钉强化的带翼缘板嵌入式连接件的抗剪性能影响较明显,而腹板厚度和接合钢筋直径的影响可以忽略。带翼缘板嵌入式连接件承载力修正计算公式与推出试验结果吻合度较好,可适用于栓钉强化的带翼缘板嵌入式连接件的设计计算。

In the PC box girder bridge with corrugated steel webs,the flanges of the embedded connectors are likely to lose stability too early and consequently lose shear resistance,and a solution to weld studs in the flanges where the width-to-thickness ratio of the plate is relatively bigger is proposed.Seven groups of full-scale specimens were prepared for push-out test,to analyze the failure mode and load-slip responses of the embedded connectors with stud-reinforced flanges under shear forces as well as the influences of multiple factors on the shear-carrying capacity of flanges,including width-to-thickness ratio of flange plate,embedded depth of webs,studs in flange plate,web thickness and the diameter of connection rebars.The applicability of the equations to calculate ultimate load bearing capacity of the embedded connectors were verified.It is shown that flange instability and cleavage cracks are the dominant failure modes of the embedded connectors with stud-reinforced flanges,and three distinctive stages are revealed in the load-slip curve,including an elastic stage,a yielding stage and a failure stage.Welding studs in the places of flanges with bigger width-to-thickness ratio prevents the occurrence of early instability of flanges,and the shear-carrying capacity of the flanges is significantly improved.The effects of width-to-thickness ratio of flange plate and embedded depth of webs on the shear-carrying capacity of the embedded connectors with stud-reinforced flanges are notable,while the effects of web thickness and diameter of connection rebars is negligible.The results obtained by the load bearing capacity modification equations agree well with the results of the push-out test,which is an alternative for the design calculation of the embedded connectors with stud-reinforced flanges.