钢桁梁桥顶推施工过程节点受力分析

Stress Analysis of Joints in Steel Truss Bridge during Jacking Construction

文中针对钢桁梁桥顶推施工问题,进行了现场应力试验,通过有限元软件建立了钢桁梁桥数值模型,研究了钢桁梁桥节点内力变化情况。结果表明,ME44节点各测点应力最大为328.5MPa,测点应力均小于材料的屈服强度330MPa。工况一接近节点底板的多数测点应力值小于工况二,上盖板上方的测点则不受影响。在实际顶推施工中,应注意千斤顶同步,避免过大的节点应力出现。在有限元数值模拟过程中,钢垫板与钢桁梁底板接触面设置为了滑移接触,无法模拟实际工程中凹角尖端位置处应力集中现象,造成了von Mises应力峰值略微偏小。

Aiming at the problem of pushing construction of steel truss bridge,the field stress test is carried out,the numerical model of steel truss bridge is established by finite element software,and the change of internal force of steel truss bridge joints is studied.The results show that the maximum stress at each measuring point of ME44 joint si 328.5MPa,and the stress at each measuring point is less than the yield strength of the material of 330MPa.The stress values of most maesuring points near the joint bottom plate in case 1 are lessh tan those in case 2,and the measuring points above the upper cover plate are not affected.In the actual jacking construction,attention should be paid to the synchronization of jacks to avoid excessive node stress.In thep rocess of finite element numerical simulation,the contact sufrace between steel backing plate and steel truss bottom plate is set for sliding ocntact,which can not simulate the stress concentration phenomenon at the tip of concave corner in practical engineering,resulting in a slightly smaller von Mises stress peak.