逐跨节段拼装连续刚构桥力学性能及桥墩参数研究

Study of Mechanical Property and Pier Parameters for Continuous Rigid-Frame Bridge Constructed Using Span-by-Span Segmental Assembly

为了解中小跨径连续刚构桥采用逐跨节段拼装施工时的力学性能,并优化桥墩设计,以洪都快速路某三跨一联(35+35+35)m等截面连续刚构高架桥为背景,运用MIDAS Civil软件模拟该桥逐跨节段拼装施工,分析连续刚构桥施工时主要控制截面的力学性能,探讨桥墩高度(6.8,10.8,14.8,18.8m)和形式(花瓶墩、独柱空心墩、双肢薄壁墩)对施工阶段、运营阶段桥梁力学性能的影响。结果表明:节段拼装施工中,各施工阶段主梁边跨跨中均受压,墩顶横梁跨中底部截面力学性能受拼装施工影响较小,墩梁固结桥墩底部截面施工阶段最大压应力达8.04MPa,温度作用对运营阶段桥梁力学性能影响最为显著;桥墩高度对成桥阶段墩梁固结桥墩底部截面应力影响明显,但墩高达到14.8m时,影响明显减弱;花瓶墩墩底截面应力受节段拼装施工及温度影响显著,采用双肢薄壁墩可有效降低温度作用对连续刚构桥墩底应力的影响。

To investigate the mechanical property of medium-sized and short span continuous rigid-frame bridge that is constructed using span-by-span segmental assembly and optimize the design of piers,a continuous rigid-frame viaduct on Hongdu Fast Corridor is taken as the background project.The bridge consists of continuous units of three equal spans of 35 meach.The finite element software MIDAS Civil was used to simulate the segmental assembly of the bridge,analyze the mechanical properties of the main control cross-sections of the continuous rigidframe bridge in the construction process,and examine the influence of pier height(6.8,10.8,14.8 and 18.8 m),pier types(vase-shaped pier,mono-columned hollow pier and double-thin-wall pier)on the mechanical property of the structure in the construction and operation stages.The results show that during the assembly,the midspan of each side span was in compression,and the mechanical property of midspan base cross-section of pier-top cross beam is not sensitive to the assembly construction,the maximum compressive stress in the pier base cross-section of the fixed pier-girder system reaches up to 8.04 MPa in the construction stage.Temperature exerts the most significant influence on the mechanical property of the bridge in the construction stage.The influence of pier height on the stress in the pier base cross-section of the fixed pier-girder system in the completed bridge state is obvious.When the pier height reaches 14.8 m,the influence distinctively decreases.For the vase-shaped pier,the influence of segmental assembly construction and temperature loading on the stress in the pier base cross-section is obvious.The double-thinwall pier can effectively reduce the impact of temperature loading on the stress in the pier-base cross-section of the continuous rigid-frame bridge.