不同下部结构型式高架桥的横桥向抗震性能研究

Study of Transverse Seismic Performance of Different Substructure Types of Viaduct

为寻求合理的抗震结构型式,以某城市高架桥(上部结构为简支小箱梁)为研究对象,采用单柱单承台、双柱单承台、双柱双承台3种下部结构型式,在相同的墩柱截面尺寸、纵筋配筋率、体积配箍率、轴压比下,建立非线性有限元数值分析模型,通过Pushover方法研究3种结构的地震破坏过程和抗震性能。结果表明:单柱单承台结构的墩底进入塑性状态,双柱单承台和双柱双承台结构的墩顶和墩底均进入塑性状态;双柱单承台的承载力较大,双柱双承台结构的承载力较小;单柱单承台结构的延性能力最高,双柱单承台结构的延性能力最低。因此,在抗震选型中应综合考虑双柱单承台结构的承载力优势和单柱单承台结构的延性能力优势。

To seek for the reasonable seismic structural types of the substructures of viaduct,an urban viaduct（the superstructure of the viaduct being a simply-supported box beam）was taken as the case study,3substructure types of the single-column pier with single pile cap,double-column pier with single pile cap and double-column pier with double pile caps were selected,the nonlinear finite element numerical analysis models for the substructures under the same sectional dimensions,longitudinal reinforcement ratios,volume reinforcement ratios and axial compression ratios of the columns of the piers were established and by the Pushover method,the seismic failure process and seismic performance of the substructures were studied.The results of the study indicate that when the footing of the single-column pier with single pile cap and the tops and footings of the double-column pier with single pile cap and double-column pier with double pile caps enter into the plastic state,the bearing capacity of the double-column pier with single pile cap is rather great while that of the double-column pier with double pile caps is rather little.The ductility capacity of the single-column pier with single pile cap is the highest while that of the double-column pier with single pile cap is the lowest.Therefore,in the selection of the seismic structural types,the advantage of the bearing capacity of the double-column pier with single pile cap and the advantage of the ductility capacity of the single-column pier with single pile cap should be comprehensively considered.