60M钢板组合梁桥钢梁施工稳定性分析

Analysis on Stability of Steel Beam Construction of 60-m Steel Plate Composite Girder Bridge

钢板组合连续梁桥因自重轻、截面较薄,在施工过程中受外荷载影响存在整体失稳和局部屈曲风险,影响桥梁施工安全。以交通部钢板组合梁桥60 m跨径进行参数分析,研究其施工阶段整体及局部稳定性。同时,对比分析了不同跨径、高跨比和横梁间距下稳定性变化规律。结果表明:(1)随着节段跨径增大,钢梁稳定系数下降,跨径每增大5 m,稳定性降低40%左右,40 m跨径时处于规范限值临界状态;(2)相同跨径下,钢梁稳定性随着梁高增大而减小,梁高超过3.5 m时,40 m跨径单梁稳定系数低于规范临界限值,结构稳定性较差;(3)横梁间距超过10 m时,缩短横梁间距可以提高结构稳定性,间距小于10 m时改变横梁间距对结构稳定性提升不大。

Because of its light weight and thin section,the steel plate composite continuous beam bridge has the risk of overall instability and local buckling influenced by the external loads during construction,which affects the safety of bridge construction.Based on the 60m span of the steel plate composite girder bridge for the parametric analysis in the Ministry of Communications,the overall stability and local stability in its construction stage are studied.The stability variation laws under the different spans,height span ratios and beam spacing are compared and analyzed.The results show that with the increase of the segment span,the stability coefficient of the steel beam decreases.The stability decreases by about 40%for every 5m of the increase of the span,and it is in the critical state of the specification limit value when the span is 40m.Under the same span,the stability of the steel beam decreases with the increase of the beam height.When the beam height exceeds 3.5m,the stability coefficient of the 40m-span single beam is lower than the critical limit of the specification,and the structuralstability is poor.When the beam spacing is more than 10m,shortening the beam spacing can improve the structural stability,while changing the beam spacing when the spacing is less than 10m has little effect on the structural stability.