软土地基桥梁的墩梁错位病害评估分析及处治

Evaluation of Pier and Beam Dislocation for Bridges on Soft Soil Foundation and Treatment

为评估软土地基桥梁的墩梁错位对桥梁结构安全的影响并进行合理的处治,以某五跨一联的城市高架桥为例进行研究。对该桥墩梁错位、墩柱倾斜开裂的病害进行应急检测、结构验算和桩土效应计算,分析病害发生的原因及影响程度。结果表明:由于桥位处于软土地基,短期内有大范围不平衡堆土,导致该联桥梁的基础和桥墩出现严重横向偏位,墩顶防落梁挡块被挤坏;大部分墩柱开裂严重,最大裂缝宽度0.63mm,墩柱最大倾斜率16.8‰;部分墩柱开裂截面已处于塑性状态,桩基的偏心受压或抗剪承载力不能满足要求,桩基横向偏位较大,最大裂缝宽度验算结果也超过规范限值。根据检测评估结果,采用临时性应急措施与永久性维修加固相结合的多层次处治方案,恢复了该桥的正常使用功能,保障了桥梁结构的安全运营。

In order to evaluate the influence of dislocation of piers and beams on the safety of bridge structures on soft soil foundation and to find out proper treatments,a five-span urban viaduct is cited as an example for the study.Emergent inspection was carried out to examine the dislocation of pier and beams as well as the inclination and cracking of the pier columns.The structure of the bridge was checked and the pile-soil interaction was calculated,and the causes of the damages and influential degree were analyzed.The results show that as the bridge stands on soft soil foundation,the large-scale unbalanced soil mounded in a short time resulted in the severe transverse displacement of the foundation and piers in that continuous unit of the bridge,and the stoppers to prevent the falling of the beams were crushed and serious cracks occurred in most pier columns,of which the maximum crack width was 0.63 mm,and the maximum inclination of pier column was 16.8‰.The cracking section of some piers had been in plastic state,the eccentric compression or shear bearing capacity of pile foundation could not meet the requirements,the lateral deviation of pile foundation was remarkable,and the calculated maximum width of crack also exceeded the limit value prescribed in specifications.According to the results of inspection and evaluation,a multi-level treatment scheme containing temporary emergency measures with permanent maintenance and strengthening was adopted.The normal function of the bridge has gone back to normal,and the safe operation of the bridge structure is assured.