孔李淮河大跨钢结构桥在整体顶推过程中的仿真及应力监测分析

发布时间：2019-01-29 05:43

【摘要】：整体顶推施工工艺在大跨连续拱桥中的应用比较少,可以查阅的资料比较少。另外,大跨连续组合拱桥在顶推过程中,由于主桥结构的边界条件不断地发生变化,造成结构体系受力也极其复杂多变。因此,为了确保整体顶推过程的安全和顺利进行,对主桥各个构件进行应力监控就非常重要。本文以孔李淮河大桥主桥结构的整体顶推为背景,基于Midas Civil有限元软件,对主桥结构所采用的三跨连续梁拱组合体系拱桥整体顶推施工过程进行仿真模拟,利用模拟结果在现场布置相关测点,得到实测数据。对应力进行对比分析,找出主桥结构在三轮整体顶推施工过程中的最不利阶段、相应截面应力的最大位置和大小,以及各结构构件的应力变化规律,为以后同类型的梁拱组合体系拱桥在整体顶推方面提供更多的参考,为同类型桥的整体顶推施工的研究提供新的思路和方向。论文主要做了以下几方面工作:第一,研究孔李淮河大桥主桥结构的施工方案及整体顶推工艺。结构采用三跨钢箱下承式连续系杆拱,三跨跨径布置为110m+180m+110m,其结构主要由三大系统构成:拱肋系统、刚性系杆(钢箱梁)和柔性系杆(体外预应力)系统、吊杆系统。该结构对应三跨分三轮进行顶推。第二,针对大桥主桥结构所采用整体顶推施工方案,根据主桥结构的构件布置形式,基于Midas Civil有限元软件建立了主桥结构的有限元模型,并定义了整体顶推过程的施工阶段的划分。第三,针对结构顶推方案进行模拟,提取仿真模拟结果。提取三轮顶推过程中主桥结构主要构件的应力包络图,找到各个构件的最不利截面位置、对应的顶推阶段和最不利的截面应力值。第四,根据模拟结果在现场布置应变传感器,采集实测结果。通过对整体顶推施工过程进行全程不间断应力(应变)监测,实现对主桥整体顶推施工的应力控制,监测主桥结构在整体顶推施工过程中每个施工阶段的结构实际受力情况。第五,对仿真与实测应力值进行对比分析。将顶推结构在第一、第二轮以及第三轮顶推过程中不利截面上测点的实测应力与仿真模拟结果进行对比分析,发现两者应力曲线的吻合程度较高,结构在顶推过程中的受力状态基本符合设计要求,以及建立的Midas Civil有限元计算模型能够很好地模拟顶推过程中构件的受力性能。
[Abstract]:The application of integral thrust construction technology in long span continuous arch bridge is less, and the data can be consulted less. In addition, due to the continuous change of the boundary conditions of the main bridge structure, the structural system is also very complex and changeable during the jacking process of the long-span continuous composite arch bridge. Therefore, in order to ensure the safety and smooth progress of the whole thrust process, it is very important to monitor the stress of each component of the main bridge. Based on the whole pushing of the main bridge structure of Kongli Huaihe River Bridge, based on Midas Civil finite element software, this paper simulates the whole pushing construction process of the three-span continuous beam-arch composite system arch bridge used in the main bridge structure. Based on the simulation results, the relevant measurement points are arranged in the field, and the measured data are obtained. By comparing and analyzing the stress, the paper finds out the most disadvantageous stage of the main bridge structure in the course of three-wheeled integral pushing construction, the maximum position and magnitude of the corresponding section stress, and the law of the stress variation of each structural member. It provides more references for the whole pushing of the same type of beam and arch composite system arch bridge in the future, and provides new ideas and directions for the research of the same type bridge's integral pushing construction. The main work of this paper is as follows: first, the construction scheme and integral pushing technology of the main bridge structure of Kongli Huaihe River Bridge are studied. The structure is composed of three main systems: arch system, rigid tie bar system (steel box girder), flexible tie bar system (external prestressing force) system, and suspender system. The structure is composed of three parts: arch rib system, rigid tie bar (steel box girder) system, flexible tie bar system (external prestressing force) system. This structure is corresponding to three-span three-wheel thrust. Secondly, the finite element model of the main bridge structure is established based on the Midas Civil finite element software, according to the integral thrust construction scheme adopted in the main bridge structure, according to the structure layout form of the main bridge structure. At the same time, the division of the construction stage of the whole pushing process is defined. Thirdly, the simulation results are extracted from the structure thrust scheme. The stress envelope diagram of the main components of the main bridge structure is extracted during the three-wheeled thrust process, and the most unfavorable section position of each member, the corresponding pushing stage and the most unfavorable section stress value are found. Fourthly, according to the simulation results, the strain sensors are arranged in the field and the measured results are collected. By monitoring the whole uninterrupted stress (strain) of the whole thrust construction process, the stress control of the whole thrust construction of the main bridge is realized, and the actual stress situation of the main bridge structure in each construction stage during the whole jacking construction process is monitored. Fifth, the simulation and measured stress values are compared and analyzed. By comparing the measured stresses on the unfavorable cross sections of the first, second and third wheeled thrust structures with the simulation results, it is found that the stress curves of the two structures are in good agreement with each other. The stress state of the structure in the process of pushing basically accords with the design requirements, and the Midas Civil finite element calculation model can well simulate the mechanical behavior of the members in the process of pushing.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U446;U445

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