高烈度区预制拼装桥梁复合减隔震体系研究

Analysis on Composite Seismic Isolation System of Prefabricated and Assembled Bridges in High Seismic Intensity Area

摘要:

超高性能混凝土连接预制拼装小箱梁桥的板式橡胶支座在E2地震作用下会发生滑动，可能使梁体位移过大而导致落梁风险，且这一风险对于高烈度地震区而言尤为明显。为改善桥梁抗震性能，基于乌鲁木齐市东进场高架标准段4×30 m连续小箱梁，针对性地提出了板式橡胶支座+水平叠层橡胶支座复合减隔震体系、板式橡胶支座+三角形钢阻尼器复合减隔震体系，并通过所建立的动力分析模型进行了桥梁抗震性能分析。结果表明：采用2种复合减隔震体系均能有效控制梁体位移，叠加三角形钢阻尼器的复合减隔震体系横向位移控制能力优于叠加水平橡胶支座复合减隔震体系；相对于常规板式橡胶支座体系，复合减隔震体系下部结构的地震内力响应有所增大，但仍保持在弹性范围内；2种复合减隔震体系所增加的费用对桥梁总体造价影响较小。

Abstract:

The plate rubber supports of ultra-high performance concrete (UHPC) continuous prefabricated assembled small-box girder bridges are prone to sliding under E2 seismic action, which may cause the excessive displacement of the girder, resulting in the risk of girder dropping. And this risk is particularly significant in high seismic intensity areas. To improve the seismic performance of bridge, based on the 4×30 m continuous small-box girder of the elevated standard section of Urumqi East Access, two composite seismic isolation systems of plate rubber support + horizontal laminated rubber support and plate rubber support + triangular steel damper are specially proposed. A dynamic analysis model is established to analyze the seismic performance of bridge. The results indicate that the two composite isolation systems can all effectively control the displacement of girder body. The composite seismic isolation system of laminated triangular steel dampers has the lateral displacement control capacity better than the system of laminated horizontal rubber supports. Compared with the conventional plate rubber support system, the seismic internal force response of the substructure of composite seismic isolation system has increased, but it still remains within the elastic ranges. The increased costs of two composite seismic isolation systems have a minimal impact on the overall engineering cost of bridge.