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为研究施工顺序对桁架桥的受力影响,对结构安全性进行评估。以某铝合金人行天桥为例,利用MIDAS软件进行施工阶段全过程分析,对比分析施工顺序不同时铝合金桁架桥的结构效应差异,定量分析了铝合金桁架桥的力学性能变化。计算得到了施工顺序改变前后该桁架桥的跨中挠度值、挠度差值和各杆件应力值及其应力差值。结果表明,缺失部分斜腹杆情况下安装主梁,然后桥面附属结构全部安装完成以后再安装缺失腹杆时,桁架桥的跨中竖向挠度最大增加1.46mm,上弦杆应力最大增加11.44MPa,下弦杆应力最大增加8.50MPa,竖腹杆应力最大增加6.53MPa,斜腹杆应力最大增加5.34MPa,约半数以上杆件的应力均发生了变化,结构的杆件不按正常的顺序施工时会降低桁架桥的承载能力。
In order to study the effect of construction sequence on the truss bridge, the structural safety is evaluated. Take an aluminum pedestrian bridge as an example, the whole construction process of the aluminum truss bridge is analyzed by using MIDAS software. The structural effects of the aluminum alloy truss bridge with different construction sequences are contrasted and analyzed. The mechanical properties of the aluminum alloy truss bridge are quantitatively analyzed. The midspan deflection, deflection difference, stress value and stress difference of the truss bridge before and after the change of construction sequence were calculated. The results show that when the main girder is installed with some slant webs absent, the maximum vertical spanwise deflection of the truss bridge can be increased by 1.46mm and the maximum stress of the upper chord increased by 11.44MPa , The maximum stress of the lower chord increased 8.50MPa, the maximum stress of the vertical web increased 6.53MPa, the maximum stress of the oblique web increased 5.34MPa, the stress of about half of the bars changed, the structure of the bar is not in the normal order of construction Will reduce the truss bridge carrying capacity.