【作者】 张晶；

【导师】 钱永久；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2013， 博士

【摘要】 砌体结构在我国桥梁工程中应用广泛,特别是山区公路建设中修建了大量的石拱桥。由于当时设计承载力偏低,并随着时间的推移,结构材料老化,各类荷载作用导致的损伤发展,其承载力逐年下降,不能满足现代交通需求。如果对这些旧的砌体桥梁进行重修,则需要花费大量的人力、物力和资金。钢筋混凝土套箍法以其能显著提高承载力、工期短、施工方便,造价低等优势,被广泛地应用于石拱桥的加固工程,但缺乏对钢筋混凝土套箍加固石拱桥形成的不同材料组成的二次受力组合加固结构的试验及理论研究。鉴于此,本文采用模型试验及理论分析相结合的方法,对套箍法加固石拱桥主拱圈(拱肋)形成的组合加固结构的受力性能及承载力的计算进行了专项的研究,取得了如下研究成果：1、通过钢筋混凝土套箍加固石砌体形成的偏心组合受压短柱进行破坏试验,全面研究了这种组合加固受压构件的受力性能。通过对不同加固设计参数(包括围套厚度、纵筋和箍筋的配筋率、偏心距以及初始应力水平)的试件进行试验及理论分析,得到各设计参数对组合加固结构受力性能及正截面承载力的影响关系；2、基于钢筋混凝土-砖石加固受压构件受力性能的试验分析,对钢筋混凝土套箍加固石拱桥组合加固截面进行了承载力极限状态分析,得到了三种极限破坏模式,并提出了界限初始应变的概念。同时通过对组合截面受力过程进行非线性全过程分析,提出了考虑加固前砌体应力水平影响的钢筋混凝土-砖石组合加固构件正截面承载力计算的非线性全过程简化计算方法；3、利用ANSYS有限元分析软件,对套箍法加固石砌体的组合加固试件的受力性能进行了非线性有限元分析,并通过与试验结果进行比较,得到分析钢筋混凝土套箍法加固石砌体加固后组合加固受压构件的有限元模拟方法。利用此模拟方法,对套箍法加固石砌体受压构件进行了扩大参数分析,深入研究了套箍效应和初始应力水平对加固组合结构承载力的影响,得到量化的影响计算系数。在此基础上,得到全面考虑套箍作用和加固前砌体应力水平影响的钢筋混凝土套箍加固石拱桥组合加固截面承载力的简化计算公式。4、通过对有植筋的混凝土和石砌体结合面的抗剪性能及强度进行试验研究,得出混凝土加固砌体工程中结合面的抗剪性能及其随植筋长度、植筋率的变化规律。结合试验通过对有植筋结合面的受力性能及破坏形式的理论分析,得出了结合面抗剪强度的计算公式,为加固设计中结合面的设计提供依据。5、通过模型试验对套箍加固石拱桥组合加固拱结构进行了受力性能及承载力研究。通过试验结果的分析得到组合加固拱结构的受力特征及破坏形式与钢筋混凝土拱相似。同时通过对加固拱承载力的分析,证明了本文前面对套箍法加固石拱桥受压构件计算分析公式的可靠性。6、通过对断渠大桥的加固实例分析,对钢筋混凝土套箍法加固石拱桥的工程应用进行了研究。研究表明采用本文的承载力计算方法进行主拱圈(拱肋)的钢筋混凝土套箍加固计算结果更精确,更靠近实际承载力,并提出了承载力极限状态的加固计算程序。更多还原

【Abstract】 Masonry structure is widely used in bridge engineering, especially a large number of stone arch high way bridges build in mountain areas in our country. The old masonry structures counld not meet the demand of modern traffic because of low bearing capacity, ageing of material and various damage caused by kinds of load. Too much money would be spent if the old structures will be rebuilt. The method to strengthen old structures by enclosed reinforced concrete is widely used in stone arch bridge because of advantages of improving significantly bearing capacity and easy construction, short construction period and economic benefits, but the research works are very less on strengthened masonry bridge. To the above situation, the specialized theorecal and experimental research works have been carried out on the strengthened structure. Conclusions are as follows:1. The mechanical behavior of strengthened compressed composite members is researched by failure experiments of eccentric compression strengthened composite columns. The influence of different design parameters on the behavior and load bearing capacity are given by changing the thickness of enclosed-reinforced-concrete, ratio of the longitudinal and hoop reinforcement, eccentricity, and existed stress level.2. Based on experimental analysis of strengthened compressed members, three failure modes and concept of bound existed strain are given by analyzing the limit state of bearing capacity, a simplified calculation method to normal section bearing capacity of strengthened compressed members accounting for existed stress level is given by nonlinear analysis of composite section.3. The nonlinear finite element analysis have been done for composite specimens strengthened by the finite element analysis software ANSYS. The simulated results are agreed with the test result very well. Influence of other parameters is analyzed by the finite element simulation method to obotain influence coefficient of enclosed function and existed stress on the bearing capacity of strengthened compressed members. Based on this, the simplified calculating method to ultimate bearing capacity is given.4. The shearing behavior and the change rule with the bar length rate is got by experiment research on the interface of new concrete to old masonry. The calculating formula of shearing strenghth is got by the theorical anysis of bearing behavior and failure model of the interface to give.5. The research on the mechanical behavior and the bearing capacity of stone arch bridge structure strengthened is done by the model experiment. It is got that the mechanics characteristic and failure model of arch strengthened is similar to the Reinforced concrete arch by the experiment. the calculation method is verified reliability.6. The research of engineering application of stone arch strengthened by reinforced concrete is done by the analysis of Duanqu Bridge strengthened. The result shows that the calculated results are more accurate, more close to the actual bearing capacity by the calculation method of this paper. The computational procedure for bearing capacity of stone arch strengthened is given.更多还原