体外预应力法在梁式桥梁加固中的应用研究

【作者】 赵强；

【导师】 宁晓骏；

【作者基本信息】 昆明理工大学 ， 道路与铁道工程， 2005， 硕士

【摘要】 随着时间的推移和经济的发展越来越多的桥梁不适应交通的需要。对所有这样的桥梁进行拆除新建将耗费非常巨大的资金,也是不可能的事,桥梁加固维修成了解决这些问题的很好办法。对桥梁加固这一热点问题,本文对作了研究公路梁式桥梁加固方法进行了研究。当今桥梁加固方法种类特别多,本文总结和分析了适合梁式梁桥的加固方法,如:加厚桥面加固法、增大梁肋加固法、钢板粘贴加固法、粘贴纤维材料加固法、体外预应力方加固法、改变结构体系加固方法等,并分别介绍了各加固方法的加固原理和特点。 本文对体外预应力加固方法进行了细致研究。体外预应力加固方法是在原有桥梁的受拉区设置体外预应力拉杆,拉杆锚固于梁的两端,给梁施加轴向压力和弯矩。因为,体外预应力拉杆所产生的弯矩与原桥梁中的不利弯矩方向相反,可以抵消部分自重应力并减小活荷载应力,从而提高梁的承载能力。这种加固方法效果显著,加固后副作用小,且能减小或避免裂缝的出现,提高梁的耐久性,能恢复或提高桥梁的荷载等级,施工时不需要凿除混凝土保护层,且损伤梁体程度小,加固时不影响或少影响交通,是一种较好的加固方法。 公路桥梁新规范的颁布和实施,要求对体外预应力加固桥梁进行新的研究。对照新实施的公路钢筋混凝土及预应力混凝土桥涵设计规范,本文对体外预应力加固作了构造分析、力学分析;分别给出了力法和虚功法求解加固体系内力计算方法;给出了加固体系在正常使用阶段的应力、挠度和裂缝等问题的计算方法;给出了加固体系的极限强度计算方法;给出了加固体系的持久和短暂状况的应力计算公式。 利用前面对各加固方法的分析结果对一实际桥梁加固所要采用的方法进行比较,并确定采用体外预应力加固方法加固。在确定采用体外预应力加固方法后,进行了加固设计计算,并用桥梁专业软件(GQJS)作了计算验证。针对体外预应力加固体系给出了其一般施工工艺。最后,对体外预应力加固体系中的一重要构件—转向块进行构造、力学分析,给出转向装置的设计计算方法。更多还原

【Abstract】 Along with time pass and economic development more and more bridges do not meet the needs of the traffic. It will consume very huge fund to dismantle and rebuild such bridge, it is impossible too. Bridge consolidating is a good solution for solving these problems. For bridge consolidating this hot question, bridge consolidate method is studied in this paper. Now the method of consolidating bridge is especially much, this paper summarized and analyzed the methods of consolidating that suit beam type bridges, for example: add bridge floor thick method, increase beam rib method, paste steel plate method, paste fiber material method, prestressed external tendons method, change structural system method, and introduced the respectively principle and characteristic of each consolidate method.This paper careful studies the prestressed external tendons method. This method is put prestressed external tendons outside the bridge’s body, tendons anchor firmly in bridge beam two ends, and exert axial pressure and curve to beam. Because the curve produced by the tendons is opposite to the original beam adverse curve in direction, can offset the stress of dead weight and reduce the stress of live load, raise the bearing capacity of beam. This kind of method of consolidating effect notable, side effect is little, and can reduce or avoid crack, raise the endurance of beam, can resume or raise the load grade of bridge, need not chisel to exclude concrete covering layer, damage beam body level is little, do not influence or less influence traffic when consolidating bridge, it is a better bridge consolidate method.The new code for highway bridges promulgate and implement need carry out new research for consolidating of prestressed external tendons method. Contrast highway new code , this text did structure analysis and mechanic analysis for prestressed external tendons bridges consolidate method; presented the calculation method for mechanics and virtual solutions;presented the calculation method for stress, deflection and crack of normally using stage for consolidated system; presented the calculation method for extremity strength of consolidate system.Using the result compared the method of consolidating for a actual bridge. When the consolidating method is determined, this text designed and calculated the example calculation, and have made verification with bridge professional software(GQJS),:and gave the common construction technology for prestressed external tendons bridges consolidate method; made structure analysis and mechanic analysis for deviators which as a part of prestressed external tendons bridges consolidate system, and give the design calculation method for deviator.更多还原