【作者】 黄成造；

【导师】 王秉纲；

【作者基本信息】 长安大学 ， 道路与铁道工程， 2010， 博士

【摘要】 随着大跨径桥梁的不断建设,基于正交异性板的钢箱梁的应用越来越普遍,钢箱梁桥面铺装修筑已成为大跨度桥梁建设的关键技术之一。国内外针对钢桥面铺装开展了不少研究,取得了一定的成果。但是由于我国车辆的重载超载严重,即使使用性能优异、价格昂贵的桥面铺装材料,常常还不能达到设计使用寿命,这说明仅仅依靠铺装材料的改进难以取得大的突破；另一方面,钢箱梁设计一般从箱梁结构安全考虑居多,未综合考虑铺装层受力要求进行钢箱梁和铺装层的一体化设计或结构优化工作。工程实践表明要提高钢箱梁桥面铺装的使用寿命需要有新的设计思路。本文针对我国钢箱梁桥面铺装设计的现状,试图从钢箱梁结构改进出发改善桥面铺装的受力状况,提出新的铺装设计思路。首先,通过较全面系统考察传统钢箱梁结构形式下各种要素对铺装力学行为的影响和经济性分析,提出了基于钢箱梁结构改进以减小铺装受力的新方法,并据此进行了新的铺装结构一体化设计研究和实桥试验研究。具体工作如下：(1)建立了基于传统钢箱梁正交异性钢桥面板铺装结构的“壳-实体”三维有限元模型,通过分析找出最有可能引起铺装层发生破坏的最不利荷载位置。研究了铺装层和钢箱梁的参数、荷载形式、温度等要素对铺装层受力指标的影响,并针对控制铺装层破坏的主要指标——最大横向拉应变,提出了一个简便的经验公式以指导铺装设计。进而对基于传统钢箱梁结构参数的改进来改善铺装受力的方法进行了经济效益分析,结果表明这些方法的代价是昂贵的。(2)从钢箱梁与铺装结构一体化的角度,提出了通过合理设计钢箱梁结构以提高钢箱梁铺装体系的局部刚度,从而达到改善铺装的受力状况的新方法。对于新建桥梁或者整体结构较弱需要加强的已建桥梁,分别推荐了可实施的、经济的小肋加劲方案。以广州珠江黄埔大桥为例,进行了钢箱梁顶板加横向小肋的改进结构的理论分析和实桥试验,试验结果证明了该方法的可行性,并提出了一个简易的经验公式指导铺装设计。(3)建立了桥梁整体结构三维鱼骨梁形式的有限元模型,研究了其整体力学行为,并进而研究了考虑全桥内力影响的铺装层力学行为。建立了以全桥内力为边界条件的箱梁铺装层一体化局部分析模型,分析钢箱梁桥面铺装在各种荷载组合下的力学响应。将考虑全桥内力影响的铺装箱梁一体化局部模型分析模型结果与正交异性板模型结果进行对比,表明正交异性板模型总体可以近似地反映铺装层和钢箱梁的受力状况,但纵横剪应力和纵向拉应力误差较大。进行了斜拉桥和悬索桥的铺装箱梁一体化局部模型分析,结果表明二者的铺装层应力有显著的不同,两者不宜简单地都采用相同的正交异性板模型分析。(4)首次将MMLS3加速加载设备应用于钢桥面铺装层的足尺试验研究,提出了基于该加速加载系统的铺装疲劳实验设计方法。通过铺装材料加速加载缩比试验,较好地模拟铺装层的实际受力环境,有效地进行了铺装材料的筛选。更多还原

【Abstract】 With the rapid development of the long-span bridges construction, steel box girders based on the orthotropic slab become more and more popular, which made the pavement on the steel box girder become one of the key point for the bridge construction. Many researches, which have got some achievements, are based on the mechanical analysis of the pavement in and out of China. However our country’s traffic conditions are very complicated, for overloaded and oversize vehicles are very common for the transportation, which results in the effect that even expensive epoxy asphalt can not make the steel bridge pavement reach its life span. It can be concluded that the pavement material improvement is not likely to be broken through. Moreover, structure designs of steel box girder are mostly considered for the structural safety, and designs for the optimizing of the pavement’s loading are very scarce, which encouraged new model and design method for the pavement design of the steel box girders.Aimed at the current pavement design situation for the steel box girder, this paper proposed a new pavement design method for the steel box girder based on reducing the dangerous loading condition by improving the box structure. Firstly, by fully and systematically investigation of the effects of key elements of the box structure on the stresses in pavement and the analysis of the economy, we recommend a new method to improve the loading condition of the pavement by the modification of the box structure, and furtherly we study the new integrative design of the pavement and the box girder, besides, some experiemtns and actual engineering tests were carried out. The details of research works are as following,(1) A three-dimensional finite element model for the steel box girder pavement system has been established based on the shell-entity elements to find out the most dangerous loading positon which led to the destruction of the pavement. The mechanical response indexes are studied by parameters of pavement deck, steel box girder, loading conditions, temperatures, and a neat and feasible empirical formula is derived for the maximum transverse tension strain. From the economic analysis for the improvement of the pavement, a new design method is required.(2) Compared to the researches which focused on the mechanical behaviors of the pavement, this paper considered the box girder and the pavement structure as aintegrative system, and proposed a method to improve the loading conditions of the pavement, which focused on improving the roof’s rigidity of the box girder by optimizing the box structures. Two methods are recommended respectively for the new bridge and the old bridge reinforcement. The method has been verified in the Pearl River Huangpu Bridge by adding small stiffening ribs at the roofs of the box girder. Moreover, a neat and feasible empirical formula is derived for the maximum transverse tension strain of this new structure.(3) Based on the three-dimensional finite element model with fishbone beam model, this paper used FEM software ANSYS to analyze the mechanical behavior of the wholes bridges, and analyzed the mechanical response of the pavement system by considering the internal forces in a bridge. We set up pavement-girder integrative local models by applying the internal forces as boundary conditions on the local models to study the mechanics responses under multiple combined loads. The analysis results are compared with these by orthotropic slab models, which shows that orthotropic slab models can reflect the mechanics behaviors approximately though the shear stresses and longitudinal tensile stresses have obvious differences. The analysis of pavement-girder integrative local models of the cable-stayed bridge and the suspension bridge also derive that the internal stresses in the pavements of the two bridges have significant different distributions, it means that it is not appropriate to analyze the two pavement stresses by the orthotropic slab models uniformly.(4) A new design method of accelerated loading test on reduced scale for the pavement material is proposed for the better meeting the engineering stress states, which helps to the choose the more duitable pavement material in the engineering.更多还原