工序变化对钢管混凝土拱桥应力的影响

为了研究钢管混凝土拱桥拱肋的上下弦管浇注混凝土顺序不同及一次性落架对拱肋应力与位移的影响，运用ANSYS有限元程序及其死活单元性质，将拱肋中的混凝土采用实体单元，钢管采用壳单元的方法，把施工步骤分为23步，模仿拱肋灌注混凝土施工过程，进行三维有限元仿真模拟分析。结果表明：一次性落架比先浇下弦管钢管轴向应力在拱脚处小102％，先浇注下弦管比先浇注上弦管钢管轴向应力在拱脚处小9．8％，施工中应尽量采用一次性落架，如有困难，应尽量采用先浇注下弦管、后浇注上弦管的施工方法，钢管可获得较高的安全储备。

Effect of different construction processes on steel-pipe-concrete-arch-bridge stress

For the purpose of studying the effect of the difference in the order of the upper and lower chords of the steel pipe concrete arch bridge' ribs pouring the concrete and the once girder on the rib's strees and placement,this paper employs the limited element programm ANSYS and the characteristic of its life and death unit to regard the concrete in the rib as a physical unit,adopts the shell unit approach to deal with the pipe,and classifies the construction procedures into 23 steps totally.The simulation analysis of the procedure of the rib pouring concrete construction is carried out.The results show that the axe orientation stress of the once girder is 102% smaller than the one of primarily-pouring lower chord pipe axe at the arch foot place,and the axe orientation stress of primarily-pouring lower chord pipe axe is 9.8% smaller than the one of primarily-pouring upper chord pipe axe at the same place.The once girder construction approach should possibly enjoy priority in practice.If it is difficult for construction,the primarily-pouring lower chord pipe approach should be adopted possibly.As far as the later-pouring upper chord pipe approach is concerned,the relatively safer reserve is available for the steel pipe.3 tabs,6 figs,(8 refs.)