影响永久性车行索道桥通行质量的桥面构造因素研究

Modern Cableway Bridge for vehicle traffic is a kind of bridge belonging to cable-beam composite structures with decks made of pavemwent slabs paved above many pieces of parallel steel cables which are anchored at both bridge ends. Although it,in comparison with other types of bridges when both their loads and span length are same, has some merits such as less material consumed, lighter self-weight，faster erection and demolishment, shorter construction period, lower cost of construction, easier maintenance, environment-friendly, etc., but its demerits ,including very poor performance on the sides of both traffic capacity and quality due to both weak overall stiffness and fragile shape-stability, exert great influence on enough expression of the advantages belonging to this type of bridges, and also limit its popularization and application. In this project, by means of three methods comprising theoretical analysis, testing real bridges, and experiments of bridge models, the influence from rigidity of pavement slabs on both dynamic and static mechanical properties will be investigated firstly. Secondly, effective indices of this kind of bridges to assess the traffic quality of bridge pavement will be studied. Thirdly, effect laws of such tectonic factors as mass per unit area and longitudinal width of pavement slabs, space between transversal beams, conformation of both main saddles at span ends and wind cables, structural parameters of guy cables,etc.,will be studied. Moreover, significant factors among them will be identified, and the tactics of tectonic optimal combimation when designing pavement system of bridges will be presented. Finally, some modification and development regarding the old design theories for cableway bridges will be done so as to give some references to popularizations and application of permanent cableway bridges. The content of this investigation in this project has theoretical meaning and practical value of engineering.

现代车行索道桥是一种在两端锚固的平行钢索上直接铺设桥面板形成桥面以承受通行荷载的索梁组合结构桥梁。在等载重、等跨径的情况下与其他桥型相比，虽然它具有用料少、重量轻、架设安装和拆除迅速、工期短、造价低、易于维修保养、环境友好等优点，但桥梁整体刚度低、桥面形状稳定性和车辆通行质量都较差、通行能力较低，严重影响了该桥型结构优势的发挥，限制了对它的推广应用。本项目通过理论分析、实桥检测和模型试验，首先拟研究桥面板刚度对该结构动、静力特性的影响规律；其次探索针对索道桥桥面通行质量的有效评估指标；再次研究桥面板单位面积质量和纵桥向宽度、横梁间距、跨端鞍座构造形式、抗风吊索布置形式和抗风索结构参数等构造因素对通行指标的影响规律，并识别出其中的显著因素，进而找出桥面构造设计的最优组合策略；最后对索道桥原有的设计理论做一些修正和发展，为永久性索道桥的推广应用提供参考。研究内容具有理论意义和工程实用价值。

现代车行索道桥的车辆通行质量差，严重影响了该桥型结构优势的发挥，亟待开展深入研究。本研究项目通过对在役实桥考察、理论分析和模型试验，首先研究了车行索道桥在运营期间的结构表现，针对非临时性的索道桥结构，提出了一些结构改进原则和具体的改进措施。其次，为了研究索道桥横梁布置方案对于桥面横倾稳定性的影响，以大跨径索道桥实例为基础，通过改变横梁形状和布置间距拟定了6种横梁布置方案，求解了各个方案的桥跨典型位置横断面处的桥面横倾角影响线，评价了各横梁布置方案的桥梁抵抗横向偏载的性能。再次，以一座大跨径索道桥实例为背景，分析了现有主索布置方案的技术经济合理性和先天结构缺陷，在此基础上提出并论证了主索布置的改进方案。最后，研究了桥面板单位面积质量和纵桥向宽度等构造因素中对通行指标影响的显著因素，找出了桥面构造设计的最优组合策略。

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