塑性铰区采用SFRC的高架桥墩抗震性能

Seismic performance of viaduct piers with SFRC in plastic hinge regions

为了改善高架桥墩的抗震性能,提出了在其潜在塑性铰区采用钢纤维增强钢筋混凝土(SFRC)进行增强的方法。对普通混凝土(NC)和钢纤维混凝土(SFC)棱柱体试块进行轴压试验,获得2种混凝土的本构关系曲线。基于结构分析软件建立全墩身采用普通钢筋混凝土(RC)和桥墩塑性铰区采用SFRC的高架桥分析模型,分析不同桥墩关键部位的地震需求。利用UCFyber程序建立桥墩截面纤维单元模型,计算桥墩抗弯能力。对比分析全墩身采用RC和桥墩塑性铰区采用SFRC的高架桥墩的抗弯能力需求比。结果表明:SFC的强度和变形能力较NC更具优势;在纵桥向地震动输入下,塑性铰区采用SFRC的桥墩比RC桥墩具有更强的塑性变形和地震耗能能力;塑性铰区采用SFRC的桥墩抗弯能力需求比平均比RC桥墩增大25.5%,具有更好的抗震安全性。

The potential plastic hinge regions of viaduct piers are reinforced with steel fiber reinforced concrete （ SFRC ） in order to improve the seismic performance of the structures .Prism specimens constructed with normal concrete （ NC ） and steel fiber concrete （ SFC ） are tested under axial compression and the constitutive relation curves of the two kinds of concrete are obtained . Models of reinforced concrete （ RC ） piers and piers with SFRC in the plastic hinge regions are＆amp;nbsp;constructed using structural analysis software ,and the seismic demands of the key parts of different piers are analyzed .The fiber element models of pier sections are established using the UCFyber program,and the flexural capacities of the piers are calculated .The flexural capacity-demand ratios of RC piers and piers with SFRC in the plastic hinge regions are analyzed and compared .The results show that the strength and deformation properties of SFC are better than NC;the plastic deformation and seismic energy dissipation of piers with SFRC in the plastic hinge regions are greater than those of RC piers under longitudinal ground motion input;the flexural capacity-demand ratios of piers with SFRC in the plastic hinge regions increase by 25 .5% on average than those of RC piers , and the seismic safety of piers with SFRC in the plastic hinge regions is better .