【作者】 郭志远；

【导师】 颜东煌； 唐雪松；

【作者基本信息】 长沙理工大学 ， 桥梁与隧道工程， 2005， 硕士

【摘要】 大跨径预应力混凝土连续箱梁桥在近二三十年来得到了广泛应用,在国内外桥梁中占有很大的比例,具有抗扭刚度大、整体性好、能承受正负弯距、施工方法成熟且易为工程单位掌握等优点。但是,在已建成的桥梁中,有相当数量的预应力混凝土箱梁桥在施工过程中或使用过程中出现大量的裂缝,严重影响了桥梁的正常使用。为此,本文进行以下预应力混凝土箱梁的开裂研究工作。1.在调研了大量钢筋混凝土结构研究理论与试验资料后,经分析比较各种混凝土本构模型,决定采用损伤理论的相关内容来进行箱梁桥的损伤分析。2.统计归纳了当前预应力混凝土箱梁中存在的种种裂缝,将各种裂缝的特点与产生原因进行分析,以期采取应对措施,控制裂缝的产生和发展。　3.应用损伤力学理论,采用从热力学出发导出的各向同性材料的损伤本构方程和损伤演化方程来进行计算分析。　4.用ANSYS 建立空间中厚壳单元模型进行箱梁空间应力场分析,计算了成桥状态恒载作用下的应力、应变场,分析了箱梁剪力滞效应对结构开裂的影响,确定了腹板应力场与腹板厚度的对应影响关系,为箱梁腹板厚度取值提供依据。　5.为将损伤力学理论应用于桥梁研究中进行了探索性的研究,将箱梁这一空间结构的开裂简化为平面问题进行损伤计算,考虑箱梁腹板双轴应力状态的特点,计入不同损伤状态下材料性能的变化,有效地进行了箱梁腹板的损伤数值计算。更多还原

【Abstract】 In recent thirty years, the long-span PC continuous box girder bridges have been widely used. They take great proportion in bridges around our country and abroad. They have the advantages of great anti-wrest stiffness, working whole well, enduring positive and negative bending well. The method of construction is mature and easy to mastering. But in many constructed bridges, there are a great deal of cracks in their constructing process or after their construction. It severely affect the normal work of the bridge. There are several contents of research about PC continuous box girder bridges in a following part. 1. After investigating many datum of theory and experiment in reinforced concrete, analyzing and comparing all kinds of models about constitutive equations in concrete, it is decided to do the analysis of damage in box girder by using the theory of damage. 2. After concluding all kinds of cracks in PC continuous box girder bridge, the characteristic and cause of cracks are analysed so some method can be taken to control crack. 3. When using the theory of damage mechanics, the damage constitutive equations derived directly from thermodynamics is adopted to do following analysis. 4. Based on the ANSYS software, a model is established by moderately-thick shell to calculate the stress and strain of box girder by self-weight after constructed, analysis the influence of shearing force lag in box girder, get the relation of the stress in box girder and the thickness of box girder, offer foundation to select the thickness of ventro-plane. 5. In order to applying the theory of damage mechanics to the research of bridge, exploring study is done. Box girder in space is simplified to plane problem to solve the calculation about damage. The speciality of bi-axis stress and the change of material performance in dissimilar situation of damage is account to accomplished the numerical calculation of damage in box girder.更多还原