边柱间距影响下桥体结构损伤演化规律

Damage Evolution Law of Bridge Structure under Influence of Side Column Spacing

依托浙江省余姚市某在建高架桥四柱预应力盖梁结构,采用数值模拟手段对不同边柱间距工况影响下的桥体力学演化机制及损伤扩展规律进行分析,并提出相应的处治措施应用于实际施工中。研究结果表明:(1)盖梁钢筋应力随着边柱间距L的增加而逐步增大,当间距达到L=23.9m工况时,纵筋上方跨中及下方两侧接近破坏强度,应考虑盖梁结构安全性问题。(2)混凝土受拉区域主要集中于盖梁部位,但随着边柱间距L的逐步增大,受拉区域逐步由盖梁传递至边柱柱顶区域。当边柱间距L>18.4m时,边柱结构损伤破坏严重,承载能力大幅下降。(3)边柱间距过大影响桥体安全性时,提出在盖梁和边柱之间由刚性连接替换成柔性铰支座以降低其受力传递效果。

Relying on the four-column prestressed bent cap structure of a viaduct under construction in Yuyao City,Zhejiang Province,the numerical simulation is used to analyze the evolutionary mechanism of bridge mechanics and law of damage expansion under the influence of different side column spacing conditions.The corresponding treatment measures are proposed to be applied in the actual construction.The results of the study show that(1)the rebar stresses of bent cap increases gradually with the increase of the side column spacing L.When the spacing reaches L=23.9 m,the upper midspan and the lower two sides of the longitudinal rebar are close to the failure strength.The safety of bent cap structure should be considered.(2)The concrete tensile zone is mainly concentrated in the bent cap,but with the gradual increase of the side column spacing L,the tensile zone is gradually transferred from the bent cap to the top zone of the side column.When the side column spacing L>18.4 m,the structural damage of the side column is serious,and the bearing capacity is greatly reduced.(3)When the side column spacing is too large to affect the safety of the bridge,it is proposed to replace the rigid connection between the bent cap and the side columns with a flexible hinge bearing in order to reduce the effect of its force transfer.