【作者】 杨化；

【导师】 樊建平； 廖碧海；

【作者基本信息】 华中科技大学 ， 桥梁与隧道工程， 2009， 硕士

【摘要】 目前县乡公路网上有大量的石拱桥在服役,这些几十年前设计修建的拱桥当时设计的荷载等级远低于它们现在承受的交通荷载,且一部分存在一定程度上的病害,如何对这些旧石拱桥的承载力进行正确评定是当前公路改建中急需解决的问题。本文利用通用有限元软件ANSYS11.0对一座试验拱桥的进行了模拟分析,有限元输出的数据结果和试验结果的对比显示了用有限元模型来模拟拱桥荷载作用下的行为特性是可行的。在此前提下,选取两种矢跨比、两种厚跨比一共三座石拱桥,对其建模进行对比分析。定量分析了拱上建筑与主拱圈的联合作用对主拱圈的承载力的贡献,以及拱上建筑的结构尺寸、材料性质等对承载力的影响;分析了矢跨比f’和厚跨比S ’对承载力的影响;总结了拱桥常见主要病害产生的原因及其对承载力影响的已有研究成果。依据有限元分析成果和已有研究成果,建立起石拱桥承载力各影响因素结构层次关系,确定了各因素权重,建立起了拱桥的表观状况与各因素分值之间的联系。综合运用层次分析法和模糊数学法,确定出石拱桥承载力修正系数Z 1,并以此对承载力检算公式进行修正,对石拱桥进行承载力检算。提出了基于外观检测的,考虑联合作用和病害影响的拱桥承载力模糊评估方法。更多还原

【Abstract】 The masonry arch bridges are in surprising numbers on the local road system of county or towns. Constructed decades ago, these bridges were designed to carry far less traffic load than they are subject to today, what’s more, quite a number of them were undermined by various defects. Thus how to assess remaining bearing capacity of these masonry arch bridges reasonably is one of the urgent problems encountered in the road reconstruction, which needs to be solved.In this paper, a numerical simulation analysis of a masonry arch bridge was carried out using the finite-element analysis program ANSYS 11.0. The result of numerical simulation analysis accords well with the results of real-bridge test, so it’s reasonable to simulate the mechanics behaviour of the masonry arch bridge under loads with the finite-element model. Under this premise, three finite-element models are established to figure out effects of the combined effect, the dimensions of spandrel construction and material property on the masonry arch bridges’bearing capacity respectively. And rise-span ration f ’, thickNess-span ration S ’are also taken into consideration. Then existing research results of the reasons that why the defects appear and the defect’s effect on arch bridges’bearing capacity were summarized. Based on the analysis results of the finite-element models and the existing research results, structure level relation of the factors affecting the bearing capacity of arch bridges was established, the weights of these factors and connection between the apparent status of the masonry arch bridges and the weight score of each factors were also defined. Using analytic hierarchy processd and fuzzy mathematics, the value of the amending coefficient Z 1 can be figure out, by which bearing capacity of arch bridges can be calculated. Till then, based on appearance inspection, a fuzzy method of assessing remaining bearing capacity of the masonry arch bridges with combined effect and the defects’effect considered was established.更多还原