部分填充混凝土薄壁带肋箱型钢桥墩拟动力试验

为研究部分填充混凝土的薄壁带肋箱型截面钢桥墩在多遇和罕遇地震作用下的非线性动力性能,制作3根试件,分别不填充混凝土、底部填充20%及40%桥墩高度混凝土,通过MTS伺服加载系统进行此类试件的拟动力试验。试验采用日本阪神地震的JRT-NS波,得到不同工况下试件的位移时程曲线、荷载-位移滞回曲线和累积滞回耗能时程曲线。结果表明:多遇地震作用下,试件均处于弹性工作状态;罕遇地震作用下,底部填充混凝土的钢桥墩处于弹塑性状态,没有明显的破坏现象,表现出良好的抗震性能;对于试验采用的钢桥墩试件,随着底部塑性铰区域混凝土填充率的增加,管内混凝土对外围薄壁钢管发生局部屈曲的约束作用逐渐增大,桥墩的结构刚度、水平承载能力、最大响应位移、残留位移、耗能能力等抗震性能指标都随之得到显著改善。

Pseudo-dynamic test study of partially concrete-filled steel bridge piers with thin-walled ribbed box sections

To investigate the nonlinear seismic performance of partially concrete-filled steel bridge piers with thin-wall ribbed box sections during frequent and rare earthquakes, three test specimens, one not filled with concrete, one filled with concrete up to 20% of the height of a bridge pier, and one filled with concrete up to 40% of the height of a bridge pier, were produced and used in the pseudo-dynamic tests using the MTS servo loading system. The JRT-NS seismic wave, the same as that in the Hanshin Earthquake in Japan, was used in the tests, from which the displacement time history curve, load-displacement hysteretic curve, and cumulative energy dissipation time history curve were obtained. The experimental results show the following: all three specimens were in an elastic state under frequent earthquakes; under rare earthquakes, specimens filled with concrete at the base were in an elastoplastic state and showed good seismic performance, without the occurrence of significant destruction; with the increase of the filling ratio of concrete in the plastic-hinge region at the base, the constraint effect of concrete inside the thin-wall steel tube on the local buckling development of the tube gradually increased; and some seismic performance indexes, including the structural stiffness, horizontal bearing capacity, maximum displacement, residual displacement, and energy dissipation capacity of steel piers, were significantly improved.