内置耗能钢板的门式箱型钢桥墩抗震性能研究

SEISMIC BEHAVIOR OF PORTAL BOX-SHAPED STEEL PIER WITH EMBEDDED ENERGY-DISSIPATING STEEL PLATES

  • 摘要: 基于可恢复功能结构设计理念,提出一种新型内置耗能钢板的门式箱型钢桥墩。开展了6榀门式箱型钢桥墩试件在变轴压和水平往复加载下的拟静力试验,通过分析试件的破坏模式、荷载-位移滞回曲线、骨架曲线、位移延性系数、刚度退化特征、强度退化系数和累积滞回耗能等性能指标,探讨了设置耗能钢板、轴压比和耗能钢板厚度等对新型门式钢桥墩抗震性能的影响规律。建立门式钢桥墩试件的有限元模型,有限元分析结果与试验结果吻合较好。研究表明:设置耗能钢板能够提升门式箱型钢桥墩的延性、变形能力和耗能能力,且能有效延缓壁板的屈曲变形和开裂。新型门式箱型钢桥墩根部壁板螺栓孔附近钢板易因应力集中而开裂,致使试件最大承载力迅速降低。随着轴压比的增大,试件的承载力、耗能能力和震后可恢复性能提高。可更换耗能钢板的厚度越小,试件的承载力越低、刚度退化越快,但其延性和耗能能力得到提升。轴压比和耗能钢板厚度对试件强度退化的影响相对较小。为便于新型门式钢桥墩的推广应用,基于试验研究结果提出内置耗能钢板的门式箱型钢桥墩的延性评估简化公式和承载力的抗震设计公式。

     

    Abstract: Based on the design concept of earthquake resilient structure, a new-type of portal box-shaped steel pier with embedded energy-dissipating steel plates was proposed. The quasi-static tests of 6 portal box-shaped steel pier specimens under variable axial pressure and cyclic horizontal loading were carried out. By analyzing the failure mode, load-displacement hysteretic curve, skeleton curve, displacement ductility coefficient, stiffness degradation characteristics, strength degradation coefficient and cumulative hysteretic energy, the effects of installation of energy-dissipating steel plate, and axial compression ratio and thickness of energy-dissipating steel plates on the seismic performance of the new-type portal steel piers were discussed. The finite element models of portal steel bridge piers were established, and the simulation results are in good agreement with the experimental results. The results show that the installation of energy-dissipating steel plate can improve the ductility, deformation capacity and energy-dissipating capacity of portal box-shaped steel piers, and can effectively delay buckling deformation and cracking of wall plates. The steel plate near the bolt hole of the wall plate at the root of the new-type of portal box-shaped steel pier is easy to crack due to stress concentration, resulting in the rapid reduction of the maximum bearing capacity of the specimens. The bearing capacity, energy-dissipating capacity and earthquake-resilient capacity of the specimens increase with the increase of axial compression ratio. A smaller thickness of the replaceable energy-dissipating steel plates leads to smaller bearing capacity and faster stiffness degradation of the specimens, as well as improved ductility and energy-dissipating capacity of the specimens. The axial compression ratio and the thickness of the energy-dissipating steel plate have relatively little effect on the strength degradation of the specimens. In order to facilitate the application of this new-type portal steel pier, a simplified formula for evaluating ductility and a seismic design formula for calculating bearing capacity of the portal box-shaped steel pier with embedded energy-dissipating steel plates were proposed based on the experimental results.

     

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