纵梁(肋)高度对正交异性板钢桥面系受力影响分析

正交异性板各个构件的选用关系着钢桥面系的安全性及经济性,通过有限元分析软件,建立桥面系板单元模型,对正交异性板多横梁体系纵梁、纵肋高度变化时桥面系各部分受力分析,总结纵梁(肋)高度变化对桥面板、横梁以及横梁与纵梁(肋)相交处挖孔部位受力的影响趋势,得出结论:增加纵梁高度,纵梁自身正应力逐渐增大,U肋正应力逐渐减小;横梁U肋挖孔处主拉应力增大,横肋相应处主拉应力减小,但减小或增大的幅度较小。改变T形纵梁高度,对横梁整体受力及桥面板影响甚小,可忽略不计,T形纵梁的合理取值范围为横梁高度的0.35~0.4倍;U肋高度过大或者过小,桥面板应力的均匀性均不好,且主拉应力均较大。增大U肋高度,纵梁正应力逐渐减小,U肋自身应力并未成线性变化趋势,而是呈"锯齿"形变化趋势。改变U肋高度对桥面板应力影响均较小,可忽略不计,U肋的合理高度取值范围为240~280 mm。

Influence of longitudinal Beam(rib) Height on the Stress of the Orthotropic Plate of Steel Bridge

The selection of components is critical to the safety and economy of bridge floor system. The plate element model of the deck is established with finite element analysis software to analyze every part of the orthotropic plate when the height of longitudinal beam or rib is changed,the influences of the change of the height of longitudinal beam or rib on the plate,cross beam,intersect excavated area of longitudinal beam( rib) and the cross beam are summed up. The results show that increasing the height of the longitudinal beam increases gradually the normal stress of longitudinal beam itself, and decreases gradually the normal stress of U rib; the principal tensile stress of the rib beam increases near the hole where the U rib cross,the principal tensile stress of corresponding local of Cross rib decreases,but the extent of decrease or increase is smaller; changing T girder height has little impact on the global stress of the cross beam,and can be ignored; the reasonable height of longitudinal beam is 0. 35 ~ 0. 4 time of the cross beam; too big or too small of the height of U ribs leads to undesirable stress uniformity of the bridge deck,resulting in bigger principal tensile stress; increasing the height of the U rib results in gradual decrease of the normal stress of the longitudinal beam,and the stress of U rib itself is not in a linear trend,but in a "zigzag"changing trend; changing U rib height has little impact on the global stress of the bridge deck slab and the reasonable height range of U rib is 240 ~ 280 mm.