基于施工质量的大跨径钢箱梁悬索桥成桥安全状态评估

发布时间：2018-09-06 11:49

【摘要】：中国境内多高山大河深谷等复杂地形,修建悬索桥具有较大优势。悬索桥构件繁多,施工专业化程度高。虽然中国在悬索桥施工技术层面已经处在世界领先水平,但是在施工过程质量变异不可避免,即施工质量与设计要求存在偏差。目前针对悬索桥施工过程中存在的施工质量变异类型、程度和成因以及施工质量变异对成桥状态的影响方式和影响的程度的研究还比较少。以施工质量变异性为全新视角,基于施工质量变异性对成桥安全状态的影响评价大跨径钢箱梁悬索桥成桥安全状态,将桥梁安全状态评估从成桥后的外观和荷载试验检测拓展至施工阶段的质量控制环节。以云南钢箱梁悬索桥为依托,通过跟踪调查山区大跨径钢箱梁悬索桥施工过程,结合现场大量线形、内力、应力等数据采集试验,系统研究了施工过程中主塔、主缆、索夹与吊杆、锚碇、钢箱加劲梁等构件质量变异的主要类型、程度及发生质量变异的原因,结果表明有14种多发性施工质量变异类型。通过有限元计算分析了施工质量变异对成桥安全度的影响方式,量化分析了施工质量偏差对悬索桥成桥状态的影响程度。研究了主塔混凝土强度变异性,几何尺寸偏差、主塔倾斜度对主塔截面应力的影响;主塔顶面水平和高程偏位、主缆架设精度、主缆截面有效受力面积对主缆受力状态的影响;主缆锚跨锚固连接器偏角对拉杆应力的影响;索夹偏位及吊杆长度偏差对主缆、吊杆内力的影响;钢箱加劲梁自重对主缆、吊杆等构件内力的影响和钢箱梁焊接残余应力对焊缝应力的影响程度。同时分析了构件内力对各种质量变异的敏感程度,并以此界定了不同类型施工质量变异性对成桥安全度的影响程度,得出了9种悬索桥施工质量变异的主控类型。提出了涵盖质量变异主控类型,以构件安全储备量为目标的,针对主塔、主缆、吊杆、加劲梁和锚固拉杆安全度的6个安全评价指标,即主塔混凝土抗压安全度(Tt)、主塔混凝土抗拉安全度(Tp)、主缆安全度(C)、吊杆抗拉安全度(D)、拉杆安全度(L)、钢箱梁应力安全度(G)作为悬索桥初始安全度评价指标,引入主成分分析法对评价指标降维处理并综合评分,实现了大跨径钢箱梁悬索桥桥成桥安全状态量化评价。结果表明,综合评分值能够充分反映基于施工质量的悬索桥初始安全状态,主成分综合评分越高,其安全度越高,综合评分值越低,其安全度越低,采用主成分分析法评价悬索桥初始安全状态可行且结果可靠。
[Abstract]:There are many high mountains, big rivers, deep valleys and other complicated terrain in China, so the construction of suspension bridge has great advantages. Suspension bridge has many components and high degree of construction specialization. Although China is already leading the world in the construction technology of suspension bridge, the quality variation in the construction process is inevitable, that is, the deviation between the construction quality and the design requirements. At present, there are few researches on the type, degree and cause of construction quality variation in the construction of suspension bridge, as well as the influence mode and influence degree of construction quality variation on the state of completed bridge. Based on the influence of construction quality variability on bridge safety, the safety status of long-span steel box girder suspension bridge is evaluated from the perspective of construction quality variability. The evaluation of bridge safety condition is extended from appearance and load test after completion to quality control in construction stage. Based on Yunnan steel box girder suspension bridge, the construction process of long span steel box girder suspension bridge in mountainous area was investigated, and the main tower and cable in the construction process were systematically studied by combining with a large number of data collection tests, such as line shape, internal force and stress, etc. The main types, degrees and causes of quality variation of cable clamps and suspenders, anchorages and stiffened steel box beams are discussed. The results show that there are 14 kinds of multiple construction quality variation types. The influence of construction quality variation on the safety degree of suspension bridge is analyzed by finite element method, and the influence of construction quality deviation on the state of suspension bridge is analyzed quantitatively. The influence of concrete strength variability, geometric dimension deviation and inclination of the main tower on the stress of the main tower section, the horizontal and elevation deflection of the top plane of the main tower, the erection accuracy of the main cable and the effective force area of the main cable section on the stress state of the main cable are studied. The influence of the deflection angle of anchor cable span anchor connector on the stress of pull rod, the influence of deviation of cable clip and length of suspender on the internal force of main cable and suspender, the self-weight of steel box stiffening beam on main cable, The influence of the internal force of the suspender and the welding residual stress of the steel box girder on the weld stress. At the same time, the sensitivity of component internal force to various quality variation is analyzed, and the influence degree of different types of construction quality variability on the safety degree of completed bridge is defined, and nine main control types of construction quality variation of suspension bridge are obtained. Six safety evaluation indexes for the safety degree of main tower, main cable, suspender, stiffened beam and anchor pull rod are proposed, which cover the main control type of quality variation and take the safety reserve of component as the target, and the safety evaluation index of the main tower, main cable, suspender rod, stiffened beam and Anchorage pull rod is put forward. That is, the main tower concrete compressive safety degree (Tt), main tower concrete tension safety degree (Tp), main cable safety degree (C), cable tension safety degree (D), tension bar safety degree (L), steel box girder stress safety degree (G) is used as the initial safety evaluation index of suspension bridge. By introducing principal component analysis (PCA) to reduce the dimension of the evaluation index and synthetically evaluate the safety state of the long span steel box girder suspension bridge, the quantitative evaluation of the safety state of the completed bridge is realized. The results show that the comprehensive score value can fully reflect the initial safety state of suspension bridge based on construction quality. The higher the principal component comprehensive score, the higher the safety degree, the lower the comprehensive score value and the lower the safety degree. It is feasible and reliable to use principal component analysis to evaluate the initial safe state of suspension bridge.
【学位授予单位】：长安大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U448.25

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