摘要
为研究高温天气下温度梯度对处于大悬臂施工阶段的宽幅矮塔斜拉桥施工的影响,通过理论计算宽幅等高箱梁的太阳辐射和热边界条件,采用Abaqus建立宽幅等高箱梁的热分析有限元模型,使用智能弦式传感器与红外测温仪实测箱梁截面温度,计算宽幅箱梁在夏季某天从日出至日落的温度梯度大小及其分布。采用Midas Civil建立施工阶段有限元模型,分析大悬臂阶段控制工况下正温度梯度对主梁线形与应力的影响规律。结果表明:热分析有限元模型结果与实测温度结果吻合较好。宽幅等高箱梁边中腹板处温度梯度效应最显著,中午高温时段内宽幅等高箱梁边中腹板顶部竖向温度梯度大小与作用范围均高于《公路桥涵设计通用规范》(JTG D60—2015)规定值。正温度梯度使主梁产生下挠,并且随着悬臂的增大,主梁下挠效应越显著,与无温度梯度相比最大悬臂节段浇筑后正温度梯度使主梁悬臂端下挠量增大了36.08 mm,尾索张拉主梁悬臂端下挠量增大了40.23 mm。正温度梯度使主梁顶板压应力显著增加。
In order to investigate the influence of temperature gradient on the construction of wide extradosed cable-stayed bridges in the large cantilever construction stage at high temperatures,the solar radiation and thermal boundary conditions of wide equal-height box girder were theoretically calculated,and the thermal analysis finite element model of the wide equal-height box girder was established by Abaqus.The cross-section temperature of the box girder was measured by intelligent string sensors and an infrared thermometer.The temperature gradient and its distribution of wide equal-height box girder from sunrise to sunset on a certain day in summer were calculated.The finite element model of the construction stage was established by Midas Civil,and the influence of positive temperature gradient on the main beam alignment and stress under control conditions of a large cantilever was analyzed.The results show that the results of the thermal analysis finite element model are in good agreement with the measured temperature results.The temperature gradient effect at the side and middle web of the wide equal-height box girder is the most significant.During the noon period at high temperatures,the vertical temperature gradient and the range of action at the top of the side and middle web of the wide equal-height box girder are higher than the specified value of the General Specifications for Design of Highway Bridges and Culverts(JTG D60—2015).The positive temperature gradient causes the main beam to deflect,and as the cantilever increases,the deflection effect of the main beam is more significant.Compared with no temperature gradient,the deflection of the cantilever end of the main beam increases by 36.08 mm after the maximum cantilever segment pouring,and the deflection of the cantilever end of the tail-cable tensioning main beam increases by 40.23 mm.The positive temperature gradient makes the compressive stress on the roof of the main beam increase significantly.
作者
朱豪杰
张谢东
李勇
林源
吴迪
ZHU Haojie;ZHANG Xiedong;LI Yong;LIN Yuan;WU Di(School of Transportation and Logistics Engineering,Wuhan University of Technology,Wuhan,Hubei 430000,China;Hubei QiaoXiao Expressway Management Co.,Ltd.,Wuhan,Hubei 430000,China)
出处
《中外公路》
2024年第5期192-200,共9页
Journal of China & Foreign Highway
基金
内蒙古自治区交通运输厅建设科技项目(编号:NJ-2013-29)。
关键词
宽幅矮塔斜拉桥
大悬臂施工
日照温度场
温度梯度
桥梁线形与应力
wide extradosed cable-stayed bridge
large cantilever construction
solar temperature field
temperature gradient
bridge alignment and stress
