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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.
Closure of the continuous rigid frame bridge construction is the need to focus on the issue, the closure of the built-in rigid skeleton design is not clear.Considering the prestressing space effect, concrete three-dimensional shrinkage and creep properties and construction process analysis, the establishment of the prestressed concrete continuous rigid The three-dimensional finite element model of the bridge was constructed.The contrastive analysis of the short and long-term mechanical properties of the closed section of the closed section with the built-in stiffening section and the external stiffening section respectively was carried out.With the steel content and cross section of the built-in stiffening section The results show that the short and long-term stress distributions of locking sections with internal and external skeletons are basically the same, the long-term stress of roof increases 20.6% on average and the floor area decreases by 30.5% correspondingly. The stress distribution is not uniform, but due to the large compressive stress reserve of the roof, the effect of the built-in strong skeleton steel is higher, the vertical distribution of the normal stress in the roof of the section is more obvious, The short-term and long-term effects are relatively small.The practical design can be considered in the steel design range of 0.27% -1.02%. Steel with the same rate Case, the skeleton built-section of the longitudinal stiffness of the closure normal stress short period, long-term effects little effect.