【作者】 陈衡治；

【导师】 徐兴； 谢旭； 叶贵如；

【作者基本信息】 浙江大学 ， 桥梁与隧道工程， 2005， 博士

【摘要】 预应力混凝土箱梁结构以其诸多优点已在桥梁工程中广泛应用,本文针对目前大跨预应力混凝土箱梁结构计算分析研究中所存在的主要问题,以杭州湾跨海大桥非通航孔工程上部结构为工程背景,对以下几方面进行了深入研究。 为提高大跨箱梁桥设计时分析的效率和精度,通过构造腹板和翼板单元,引入高次轴向位移函数,和采用自由度缩减技术,提出了基于板梁理论的考虑翘曲、剪力滞、畸变和板厚变化等影响的大跨箱梁桥整体分析方法,并以工程背景为例,与实体元结果进行了对比验证。 以通用有限元软件为平台,创建了快速三维实体建模方法,并提出预应力结构空间实体分析的等效节点力法。通过工程实例的仿真计算,显示该方法具有直观、详尽、精确等特点。为三维实体有限元在箱梁结构设计验算中的推广应用提供了有效的支持。 针对大吨位预应力群锚局压区研究中的不足,以工程背景为例,从各类规范方法计算分析、考虑锚具影响的三维实体有限元仿真及施工现场的应力测试分析等多方面对预应力砼箱梁在大吨位预应力群锚作用下的局压强度和抗裂性进行了研究。 在预应力砼箱梁温度应力场计算方法研究中,基于箱梁表面热交换平衡理论,建立了采用热瞬态分析和热—结构耦合求解技术计算温差应力场的方法,该方法可有效考虑气温地理环境等条件的影响。并与按公桥规温度模式计算比较,在得出大跨砼箱型梁桥温度效应特征的同时,指出了规范方法的不足。另一方面,提出了砼箱梁浇筑养护方案的数值评估方法,在与实测结果对比验证的基础上,以工程背景的整体预制砼箱梁的施工方案为例,对各种控制箱梁水化热的常用方法进行评估。为大跨预应力砼箱梁在浇筑阶段和运营阶段的温差裂缝控制提供了有力的理论保障。 为更精确有效地分析预应力砼箱梁结构体系的极限状态特性,建立了考虑双非线性的有限纤维梁段元法,并提出考虑全自由度的位移增量法,同时进行了原形梁极限承载试验以验证该方法精度。针对先简后连结构体系,提出了考虑施工过程影响的承载力计算方法,并以工程背景为例,分析其极限承载能力,同时还研究了结构在进入塑性后的内力重分布规律。 本文所得出的主要结论和研究成果可供预应力混凝土箱梁桥的计算设计和施工作参考。更多还原

【Abstract】 PC box-girder structure, with its various advantages, has been widely applied in bridge engineering. The aim of this research project is to deal with the existing problems in the calculation and analysis of the PC box-girder structure with long-span. On the basis of an engineering practice of non-navigable channel superstructure of Hangzhou Bay Bridge, in-depth research has been carried out on the following aspects.To develop a simplified calculation method for the global analysis of the PC box-girder structure, the units of web plate and wing plate were constructed, and the high order axial displacement function was introduced. As a result, based on the plate beam theory it put forward the method of global analysis which takes account of warping, shear log, distortion and the variation of the plate thickness. The accuracy and efficiency of this method has been validated by comparing with the results of the solid element.In the accurate calculation research of the PC box-girder structure, the finite element software has been used as a platform to create expedite model of the entity in three-dimension, and the equivalent nodal force method has been introduced to analyze the entity of PC box structure in the space. It is observed that this method is direct, detailed and precise, when simulating the real engineering projects.The purpose of the calculation and experimental research of anchorage zone under the effect of large-tonnage PC anchors is to validate the blueprint of the non-navigable channel superstructure of Hangzhou Bay Bridge. To calculate, validate and analyze the anchorage strength and crack resistance of the PC box-girder under the effect of large-tonnage PC anchors, several different normative calculation methods have been compared, three-dimensional finite element method has been used to simulate the entity under the effect the anchor devices and the results from the stress testing on spot has been analyzed.In the temperature and stress field calculation methodology research of the PC box-girder, based on the finite element principle and the consideration of geography and temperature, a method is developed to calculate the stress field under different temperatures by using thermal instantaneousanalysis and thermal-structural coupling analysis techniques. Depend on the calculation, the characteristics of the temperature effect on the PC box structured bridge was summarized. By comparing the results with the public bridge temperature normative calculation, on one hand the deficiencies of the normative calculation method has been shown, on the other hand the statistics evaluation method of maintaining and building the PC box has been put forward. The accuracy of this method was proved by comparing with the experimental results. In addition, various normal ways in controlling the temperature of the PC box were evaluated with the example of construction blueprint of global pre-molding of PC box of Hangzhou Bay Bridge. Finally it discussed the changes of temperature, stress in the early stage, so that some suggestions were given about the anti-crack measures in the early stage.In the ultimate bearing capacity calculation research of PC box-girder structure, the non-bilinearity finite fabric sect element method and the displacement increment methods with full freedom were set up. The precision efficiency of different increment methods were compared by calculatbg examples. The bearing capacity experiment of the original girder model was also carried out to investigate the features of its limit state and to validate its applicability and accuracy. Take example by Hangzhou Bay bridge, the bearing capacity of the PC box-girder structure in the process of construction was calculated and the redistribution law of the internal force in the structure which develops plasticity was investigated.The conclusion and research results in this thesis can be taken as reference to the calculation design and construction of the PC box-girder structures.更多还原