新型预制节段拼装桥墩抗震性能及塑性铰区变形分析

Seismic performance of new connection precast segmental piers and deformation analysis of plastic hinge zones

为探究采用两种不同连接方式(Fiber Reinforced Concrete(FRC)+锥套锁紧纵筋和Ultra-High Performance Concrete(UHPC)+纵筋错位搭接)预制节段拼装桥墩塑性铰性能,设计并制作了4组大比例缩尺(1∶2.5)桥墩。通过拟静力试验,采用数字图像相关(Digital Image Correlation,DIC)技术得到应变场和位移场,利用应变场和位移场捕捉并计算4个桥墩试件塑性铰区的裂缝发展趋势和宽度。结果表明:在大比例尺试件上,采用DIC技术测量位移具有较高的可靠性。4个桥墩试件加载至中高水平荷载时塑性铰区位移呈现非线性变化,具有明显的塑性位移发展趋势;两种连接方式接缝处裂缝宽度约为其他部位的2~8倍,表明接缝处为预制节段拼装桥墩变形的主要集中区域。

In order to explore the plastic hinge performance of precast segmental piers designed by two different connections(fiber reinforced concrete(FRC)+taper sleeve locking longitudinal reinforcement and ultra-high performance concrete(UHPC)+staggered longitudinal reinforcement),four pier specimens with a large-scale(1∶2.5)were designed and fabricated.Based on the pseudo-static test,the strain field and displacement field were obtained by DIC(Digital Image Correlation)technique,and the strain field and displacement field were used to capture and calculate the crack development trend and crack width of plastic hinge zone of four pier specimens.The results show that the DIC technique has a high reliability in measuring displacement of large-scale specimens.The displacement of the plastic hinge zone of four specimens exhibited a nonlinear change when they were loaded to a higher level,and an obvious trend of plastic displacement could be observed;the crack width at the post-cast joint is about 2-8 times that of the other part,indicating that the postcast joint is the main concentrated area of deformation of precast segmental piers.