合龙段内置劲性骨架对刚构桥受力性能的影响

发布时间：2018-04-10 11:22

本文选题：连续刚构 + 合龙段　；参考：《应用基础与工程科学学报》2017年02期

【摘要】：合龙方式是连续刚构桥施工中需要重点关注的问题,合龙段内置劲性骨架设计缺乏明确说明.考虑预应力空间效应,混凝土三维收缩徐变特性和施工过程分析,建立了预应力混凝土连续刚构桥的三维精细化数值模型.对合龙段分别采用内置劲性骨架和外置劲性骨架的合龙段短、长期力学特性进行了对比分析.对内置劲性骨架的含钢率、截面形式进行参数分析.研究结果表明:内、外置骨架锁定的合龙段短、长期应力分布基本相同,顶板长期应力较短期应力平均增加20.6%,底板处相应减少30.5%.内置骨架锁定更易形成顶板的长期应力分布不均,但由于合龙段顶板压应力储备较大,其影响较小.内置劲性骨架含钢率越高,合龙段顶板的纵向正应力分布不均越明显,含钢率对底板应力的短、长期效应影响均相对较小.实际设计中可考虑采用的含钢率设计范围为0.27%-1.02%.含钢率相同的情况下,内置劲性骨架截面形式对合龙段纵向正应力短、长期效应影响很小.
[Abstract]:Closure is an important problem in the construction of continuous rigid frame bridge.Considering the spatial effect of prestressed concrete, the three-dimensional shrinkage and creep characteristics of concrete and the analysis of construction process, the three-dimensional fine numerical model of prestressed concrete continuous rigid frame bridge is established.The short and long term mechanical properties of the closure segment with internal rigid skeleton and external rigid skeleton are compared and analyzed.The steel content and section form of the built-in rigid skeleton are analyzed.The results show that the internal and external skeleton locking closure segment is short and the long-term stress distribution is basically the same. The long-term stress of the roof is increased by 20.6than that of the short-term stress, and the bottom plate is reduced by 30.5.The long term stress distribution of the roof is more easily formed by the locking of the built-in skeleton, but the influence is small because of the large compressive stress reserve of the roof in the closure segment.The higher the steel content of the inner frame is, the more uneven the longitudinal normal stress distribution of the roof is, the shorter the steel content ratio is to the stress of the bottom plate, and the smaller the long-term effect is.The design range of steel-content ratio is 0.27- 1.02in practical design.When the steel content is the same, the longitudinal normal stress is short and the long-term effect is small.
【作者单位】：山东大学岩土与结构工程研究中心;
【基金】：国家自然科学基金青年基金项目(51108249)
【分类号】：U445.4;U448.23

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