外包钢套加固震损双层高架桥框架式桥墩抗震性能评估与参数分析

Parameter Analysis and Evaluation on Seismic Performance of Seismic-damaged Frame Piers of Double-deck Viaduct Strengthened by Steel Jacket

基于《公路桥梁抗震设计规范》“两阶段”设防原则,采用SAP2000有限元软件建立震损加固桥墩数值模型,通过构建与设防水准地震相匹配的结构性能水准,选取基底剪力和墩顶位移作为结构性能评价指标,建立基于能力需求比的双层高架桥墩抗震性能评估流程,从抗震性能和损伤修复效果角度,对外包钢套含钢量和强度的影响进行分析。研究结果表明,中度损伤试件经外包钢套加固后基底剪力和墩顶位移能力需求比分别提高了76.72%、62.93%,重度损伤试件经外包钢套加固后基底剪力和墩顶位移能力需求比分别提高了62.98%、51.94%;当外包钢套含钢量ρ<0.98%时,重度损伤加固试件基底剪力能力需求比呈负向增长,承载能力修复效果不理想;当外包钢套含钢量ρ>2.08%时,中度损伤及重度损伤加固试件墩顶位移能力需求比提高率大于基底剪力,此时变形能力修复效果优于承载能力;提高外包钢套强度显著增强了中度损伤和重度损伤加固试件承载能力,但变形能力基本不提高。

Based on the“two-stage”fortification principle of bridge specification,SAP2000 finite element software was used to establish the numerical model of seismic damage reinforced piers.By constructing the structural performance level matched with the fortification level earthquake,the base shear force and the displacement of pier top were selected as the structural performance evaluation indexes,and the seismic performance evaluation process of double-layer viaduct pier based on the capacity-demand ratio was established.From the perspective of seismic performance and damage repair effect,the parametric influence analysis on the content of outsourcing steel and the strength of outsourcing steel sleeve was completed.The results show that the base shear and pier top displacement capacity requirements of the moderate damage reinforced specimens are increased by 76.72%and 62.93%respectively,and the severe damage reinforced specimens are increased by 62.98%and 51.94%respectively.When the outsourcing steel contentρ<0.98%,the base shear capacity demand ratio of severe damage reinforced specimens increases negatively,and the bearing capacity repair effect is not ideal.Whenρ>2.08%,the increase rate of displacement capacity demand ratio of moderate damage and severe damage reinforced specimens is greater than that of base shear,and the repair effect of deformation capacity is better than that of bearing capacity.The bearing capacity of the strengthened specimens with moderate and severe damage is significantly enhanced by increasing the strength of the wrapped steel sleeve,but the deformation capacity is basically not improved.