聚氨酯-钢板复合材料正交异性桥面板稳定性能研究

It is a new development direction of steel bridge and transformation that sandwich board of polyurethane-steel plate composite material was introduced into the bridge structure.The nature of the composite material is essentially different from that of sandwich board commonly used in house building today, the former can withstand the vertical board wheel load, mechanical performance is good, and the total cost is low. it has many advantages to replace conventional orthotropic steel bridge deck. The project will try to solve the algorithm of the buckling elastic stable performance of orthotropic sandwich bridge deck, which is the sandwich structure with the rigid polyurethane as the core layer, in the complex stress state of parallel and vertical board face and complex supporting conditions, trying to use the energy principle and the variational method, on the basis of sandwich plate theory and orthotropic plate theory. And the influence laws will be researched by means of the simulation calculation and test method , which are about the overall stability and local stability of the orthotropic sandwich bridge deck of polyurethane-steel plate composite material in changing parameters of the core layer thickness, the thickness of the steel plate, stiffening rib spacing, physical properties of core material,.etc. as well as to ascertain the physical performance indexs of polyurethane core layer to meet the force requirements of sandwich bridge deck.The purpose is to provide the theory and experiment foundation for the composite materials in the application of the bridge, greatly reduce the stiffening rib quantity of long-span steel bridges and the emergence of weld crack, and enhance the anti-fatigue performance and damping performance, etc.

聚氨酯-钢板复合材料夹层板引入桥梁结构是钢结构桥梁及桥梁改造方面一个新的发展方向，该复合材料结构与现今常用于房屋建筑的夹层板结构性质上有本质区别，前者能承受垂直板面的重载，力学性能好，成本低，用来代替常规的正交异性钢桥面板具有很多优点。本项目在夹层板理论、正交异性板理论的基础上，尝试用能量原理及变分法等分析以硬质聚氨酯为芯层的正交异性夹层桥面板，在面内和面外复杂受力状态以及复杂支承条件下的弹性屈曲稳定性能求解。并通过模拟计算及试验测试方法研究聚氨酯-钢板复合材料正交异性夹层桥面板在芯层厚度、钢板厚度、加劲肋间距、芯材物理性能等参数变化时，对板的整体稳定、局部稳定的影响规律，确定满足夹层桥面板受力要求的聚氨酯芯层材料各物理性能指标及检验方法。为该种复合材料在桥梁上的应用提供理论及试验基础，从而大量减少大跨径钢桥的加劲肋数量及焊缝裂纹的出现，增强抗疲劳性能及减振性能等。

聚氨酯-夹层板是一种在两层钢面板之间注入聚氨酯芯层，待聚氨酯凝固之后，与钢面板牢固粘结、共同受力组成的新型复合结构。此种结构引入桥梁结构是钢结构桥梁及桥梁改造方面一个新的发展方向，然而在国内这种聚氨酯-钢板夹层结构桥面板的研究除本课题组外，尚未见其他相关成果报道。本文以模型试验为基础，开展聚氨酯-钢板夹层结构桥面板受力性能研究为聚氨酯-钢夹层结构技术在国内的应用提供可靠的依据。依据现有的一些工程实例构造进行取值，根据模型相似原理进行了试验方案的设计，进行了试验研究。通过试验值与有限元计算值对比分析得到了两种加劲肋间距的夹层板受力规律，有限元分析结果与试验值比较吻合。在试验模型的基础上，进行了相同加劲肋间距的普通正交异性钢桥面板和夹层桥面板有限元对比分析。验证了聚氨酯-钢板夹层结构增补层用在正交异性钢桥面板修复和加固中时，能很大程度上提高原桥面板的刚度及承载力，并能有效降低关键位置处的应力水平及应力变化幅值；并得到了普通正交异性钢桥面板盖板主要是面外的弯曲应力，夹层板顶钢板、底钢板应力成分中薄膜应力占据主要成分。对建立的三种加劲肋间距的夹层板模型在相同工况荷载作用下关键截面应力变化曲线进行对比分析，并将它们与普通正交异性钢桥面板最大挠度值、盖板最大应力值分别进行对比分析，得到：普通正交异性钢桥面板盖板以横向应力为主要控制应力，而夹层结构桥面板盖板纵、横向应力最大值相差不大；夹层桥面板弹性体对钢板提供连续的支撑，使得挠度值、局部最大应力值显著降低。因此消除了密集的加劲肋的需要，可以大大减少加劲肋的数量。试验结果也显示了夹层板面板压应力峰值，拉应力峰值的一些变化规律。通过研究聚氨酯-钢夹层板随着芯层厚度的增加，对夹层板模型关键截面顶板顶面、底板底面应力变化进行对比分析，得到了其对芯层厚度参数变化的敏感顺序。