大跨度斜拉悬索组合体系桥梁换索施工监控技术研究

发布时间：2018-11-19 07:09

【摘要】：斜拉桥和悬索桥是目前大跨度桥梁最常用的两种桥型。在桥梁受到建设条件的制约时，采用斜拉—悬吊协作体系结构往往能体现出更好的技术经济优势。但由于结构受力复杂，该类桥梁营运多年后，受到混凝土徐变、收缩、拉索的松弛及疲劳荷载等影响，结构线形和内力发生变化，导致斜拉索内力重分布，部分超过其允许强度甚至断索，而不得不换索。由于斜拉—悬索体系桥梁属高次超静定结构，换索施工方法、现场施工荷载与环境的不断变化都将导致施工过程中的内力和位移偏离设计值，这种偏离积累到一定程度如不及时加以调整修正，换索施工过程中结构的安全状态将难以保证。因此，必需对换索施工的每一阶段进行详尽的分析、验算，求得斜拉索张拉力和主梁挠度、塔柱位移等施工控制参数的理论计算值，明确施工顺序，并在施工中对线形及内力进行严格监测和控制，及时掌握结构的实际状态，进而对施工步骤及控制条件做出调整，防止施工中的误差积累，保证全桥线形与结构安全。针对该类桥梁结构的特殊性，施工监控主要是对主梁的线形、应力和斜拉索的张拉力进行三控；控制的最基本要求是确保施工中结构的安全，其次必须保证结构的几何线形和内力在设计要求的容许误差范围之内。本课题以乌江大桥维修加固工程为依托，重点研究了换索过程中塔、梁、索的监控方法、结果分析及索力调整等技术。首先对乌江特大桥进行建模分析，，分别利用MIDAS和ANSYS软件进行全桥建模，对全桥的初始状态以及换索过程进行动态模拟；对全桥初始状态，根据前期检测结论，针对本桥构件出现的主要病害，对构件承载能力不同程度的劣化，进行承载能力折减，截面折减，进而模拟结构初始状态。其次根据换索顺序，进行全桥内力、应力以及索力计算，确定了合理的换索初张力以及全桥调索索力值。最后针对换索、调索过程中结构内力、索力的变化，对比分析理论计算与实测结果；对其过程中各索力变化限值、主塔偏位情况、主梁应力变化情况以及线形变化情况进行跟踪监测，并及时在理论模型中进行参数修正，指导换索施工，得到各换索、调索过程中各参数变化情况。通过全过程监控保证桥梁施工安全，确保成桥后结构受力和线形满足设计要求的同时，通过进一步的深入分析总结，为日后同类桥梁的更换施工提供参考和借鉴。
[Abstract]:The cable-stayed bridge and suspension bridge are the two most commonly used bridges at present. When the bridge is restricted by the construction conditions, the use of cable-stayed suspension cooperation system structure can often reflect better technical and economic advantages. However, due to the complexity of the structure and the influence of concrete creep, shrinkage, relaxation of cables and fatigue load on the bridge after many years of operation, the structural line shape and internal force are changed, which results in the redistribution of the internal force of the stay cable. Part exceeds its allowable strength even breaks the cable, but has to replace the cable. Because the cable-stayed suspension system bridge belongs to the high-order statically indeterminate structure, the construction method of changing cables, the continuous change of site construction load and environment will cause the internal force and displacement to deviate from the design value in the construction process. If this deviation accumulates to a certain extent, it will be difficult to ensure the safety state of the structure in the process of cable replacement construction if it is not adjusted and corrected in time. Therefore, it is necessary to carry out detailed analysis and checking calculation for each stage of cable replacement construction, to obtain the theoretical calculation values of construction control parameters such as cable tension, deflection of main beam, displacement of tower column, etc., and to define the construction sequence. In the construction, the line shape and internal force are strictly monitored and controlled, the actual state of the structure is grasped in time, and then the construction steps and control conditions are adjusted to prevent the accumulation of errors in construction, and to ensure the safety of the whole bridge alignment and structure. In view of the particularity of this kind of bridge structure, the construction monitoring is mainly to control the line shape, stress and tension of the main girder. The most basic requirement of control is to ensure the safety of the structure in construction. Secondly, the geometric alignment and internal force of the structure must be within the allowable error range of the design requirements. Based on the maintenance and reinforcement project of Wujiang Bridge, the monitoring methods of tower, beam and cable in the process of cable exchange, the analysis of the results and the adjustment of cable force are studied in this paper. Firstly, the model of Wujiang super bridge is analyzed, and the whole bridge is modeled by MIDAS and ANSYS software, and the initial state of the bridge and the process of cable exchange are simulated dynamically. For the initial state of the whole bridge, according to the early detection conclusion, aiming at the main diseases of the bridge component, the bearing capacity of the member is reduced, the section is reduced, and the initial state of the structure is simulated by varying degrees of deterioration of the bearing capacity of the member. Secondly, according to the sequence of cable exchange, the internal force, stress and cable force of the whole bridge are calculated, and the reasonable initial tension and the cable force of the whole bridge are determined. Finally, according to the change of internal force and cable force in the process of changing cable and adjusting cable, the theoretical calculation and the measured results are compared and analyzed. The limit value of cable force, the deflection of main tower, the stress change of main beam and the change of linear shape are tracked and monitored, and the parameters are corrected in time in the theoretical model to guide the construction of cable replacement, and the cable replacement is obtained. The variation of parameters in the process of cable adjustment. In order to ensure the safety of bridge construction through the whole process of monitoring and control, to ensure that the force and alignment of the structure after completion of the bridge meet the design requirements, and through further in-depth analysis and summary, to provide reference and reference for the replacement construction of similar bridges in the future.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445.4

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