可“临-永”转换抢修钢墩设计及应急使用稳定性

Design and Stability of Rush-repair Steel Piers with Temporary-Permanent Conversion for Emergency Use

为解决既有桥墩抢修器材仅适用于临时抢修、不能与永久恢复有效结合的问题,提出一种可“临-永”转换抢修钢墩,并介绍其结构组成和结构特点。针对应急使用阶段,基于Abaqus建立空间模型开展结构稳定分析,考虑列车活载、横向风载、制动力、平面扭转、初始缺陷等影响因素,分别从线弹性和非线性两个层面系统研究应急使用状态结构稳定性能。研究表明:线弹性分析时,随着横向风压增大,钢墩临界荷载呈减小趋势,下降速率与列车荷载强度及活载加载图式相关;钢墩临界荷载随着平面扭角增大呈减小趋势,具体使用时宜将扭转角度控制在0.5°以内,此外,平面扭转发生位置越低,对结构稳定影响越明显;钢墩临界荷载随几何初始缺陷增大呈下降趋势,不同类型缺陷对钢墩稳定的影响程度由大到小为双向缺陷、横向缺陷、纵向缺陷;考虑非线性影响时,双重非线性影响最大,材料非线性次之,几何非线性最小。

In order to solve the problem that the existing bridge pier repair equipment is only suitable for temporary rush repair and cannot be effectively combined with permanent restoration,a temporary-permanent conversion rush-repair steel pier was proposed.The structure composition and characteristics were introduced.In response to its emergency use stage,a spatial model was established based on Abaqus to carry out structural stability analysis.Considering the influence factors such as train live load,lateral wind load,braking force,plane torsion and initial defects,the structural stability performance in emergency use was systematically studied from two aspects of linear elasticity and nonlinearity.The results show that the critical load of steel pier decreases with the increase of lateral wind pressure in linear elastic analysis.The rate of descent is related to the train load intensity and the live load pattern.The critical load of steel pier decreases with the increase of the plane torsion angle,and the torsion angle should be controlled within 0.5°during specific use.In addition,the lower the plane torsion occurs,the more obvious the impact on the structural stability.The critical load of steel pier decreases with the increase of geometrical initial defects.The bidirectional defects have the greatest influence on structural stability,followed by transverse defects and longitudinal defects.Considering the nonlinear effects,the double nonlinear effect is the greatest,followed by the material nonlinear effect and the geometric nonlinear effect.