290m空腹式刚构桥三角区箱梁施工支架受力分析

针对贵州北盘江大桥三角区特殊的构造,提出了下弦采用挂篮施工并辅以扣索张拉,上弦采用支撑于下弦顶面的施工支架现浇施工方法.建立了三角区箱梁、扣索和施工支架于一体的有限元模型,开展了3种不同工况下的施工支架力学分析.计算结果表明:施工支架立柱内力受下弦梁段浇筑、扣索张拉和预应力张拉等影响较大,会出现内力集中现象.

Mechanics Analysis of Construction Bracket for 290m Spandrel Rigid Frame Bridge

Based on the special construction details at spandrel zone of Beipanjiang Bridge,the construction with cantilevered segmental method in the lower chords and on-site construction of bracket in the upper chords were conducted.A finite element model including box girders,cables and brackets was built;the mechanics analysis of the bracket in three different cases was performed.The results demonstrated that lower chords girder concrete casting,cables and pre-stress bars tensioning exerted great influence on internal forces of bracket columns;internal forces concentration would occur.