为研究刚性悬索加劲钢桁梁施工过程中的各种随机误差参数对结构效应的影响,采用ANSYS程序建立参数化模型。将大桥施工过程中的制作安装误差参数定义为随机变量,运用Monte-Carlo随机有限元法,进行东江大桥施工全过程随机有限元分析,研究在随机参数影响下结构响应的频度、均值和标准差,并进行参数敏感性分析。研究结果表明:受随机误差参数的影响,结构行为呈现较强的随机性,成桥后结构响应的均值与其确定性计算结果的产生较大偏差,且存在较大的变异性,使得成桥后中支点附近杆件应力超过容许值的概率大增;通过参数敏感性分析发现,结构恒载、刚度及桥门架偏位这三项误差对结构杆件应力影响较大,是施工中应主要控制的误差参数。而横向内力调整误差对结构应力的影响也不容忽视。
To research the effect of all kinds of random errors on Dongjiang bridge,a steel truss bridge stiffened with rigid cables. ANSYS program was used to establish a parametric model,in which all kinds of error parameters were defined as random variables. Based on the Mente-Carlo stochastic finite element method,the model simulated the whole construction process of the bridge,and investigated the frequency,mean value and standard deviation of the structure's stress and deflection,and study sensitivity of all defined error parameters about some performance. The result shows that the uncertainty of error parameters lead some randomicity to the mechanical behavior of the bridge,and the deviation between mean value and certain value increase meanwhile the variability of structural responses become more significantly,the probability of stress of some chords nearby middle support exceeding the allowance value correspondingly increase higher; through the sensitivity analysis of all error parameters,it knows that the errors exited in dead loads,stiffness and dyssymmetry of portal frame have significant effect on stress of trusses,those must be controlled strictly in construction process. Meanwhile,the effect of error exited in lateral internal force adjustment could not be ignored.