基于墩柱增设的独柱墩曲线箱梁桥抗倾覆研究

Research on anti-overturning of curved box girder bridge with single column pier based on the addition of piers and columns

近年来,独柱墩曲线箱梁桥整体侧翻倾覆事故时有发生,开展抗倾覆分析及加固对策的研究具有重要的工程价值。以某匝道桥为工程背景,考虑其抗倾覆稳定性,使用支座失效法并结合有限元分析软件Midas/Civil建立柔性梁格有限元模型,对独柱墩曲线箱梁桥加固前后的抗倾覆稳定性和动力特性进行了对比分析。研究结果表明:加固前该桥曲线箱梁的一阶振型为扭转振动,在4号墩处,易发生扭转,可能导致支座脱空,此时该桥抗倾覆稳定系数最小为1.97,不满足规范中抗倾覆稳定系数不小于2.50的要求。采用墩柱增设法对4号墩进行加固后,该桥曲线箱梁的一阶振型为纵向弯曲振动,抗倾覆稳定系数最小为4.31,抗倾覆能力得到显著提升。通过现场抗倾覆稳定性静载试验,对加固效果进行了实桥验证,效果较好。

In recent years,overturning accidents involving curved girder bridges with single-column piers have occurred frequently,underscoring the critical engineering significance of conducting antioverturning analysis and developing effective reinforcement strategies.This study focused on a specific ramp bridge,evaluating its anti-overturning stability by using the bearing failure method and finite element analysis software Midas/Civil.A flexible girder lattice finite element model was established to compare and analyze the anti-overturning stability and dynamic characteristics of the curved girder bridge before and after reinforcement.The results indicate that,prior to reinforcement,the first-order mode of the curved box girder of the ramp bridge exhibited torsional vibration,particularly prone to torsion at pier 4,potentially leading to bearing voids.The minimum anti-overturning stability coefficient was found to be 1.97,failing to meet the required minimum of 2.50,thus indicating insufficient anti-overturning capacity.Post-reinforcement,with the application of additional piers and columns to pier 4,the first-order mode of the curved box girder shifted to longitudinal bending vibration,and the minimum anti-overturning stability coefficient increased to 4.31,demonstrating a significant enhancement in anti-overturning capacity.The efficacy of the reinforcement was further validated through an on-site static load test,which confirmed the positive impact of the implemented measures.