单肢高墩连续刚构桥施工全过程稳定性及参数分析

发布时间：2018-04-12 19:40

本文选题：连续刚构桥 + 单肢高墩　；参考：《长沙理工大学》2015年硕士论文

【摘要】：连续刚构桥是墩梁固结的组合体系,其综合了连续梁桥和T形刚构桥的优点,在我国的桥梁建设中得到广泛应用。目前国内外对大跨度连续刚构桥施工过程和成桥状态的稳定性方面的研究已较深入,但大多数文献研究针对的是双肢薄壁高墩连续刚构桥,针对单肢薄壁高墩连续刚构桥的稳定性研究不多,与双肢高墩相比其稳定性有着自身特点,针对性的对单肢薄壁高墩连续刚构桥开展稳定性研究,具有一定的工程价值和研究意义。本文依托湖南湘西龙永高速上的红岩溪特大连续刚构桥为工程背景,对单肢高墩连续刚构桥悬臂施工过程和成桥状态的稳定性问题开展研究,主要研究工作和成果如下:(1)阐述了国内外连续刚构桥的发展历程和研究现状,简要介绍了结构稳定性研究的基本理论,工程结构稳定性评价指标和判别准则。(2)使用有限元软件Midas/Civil建立了红岩溪特大连续刚构桥计算模型,并且对其进行静力分析,得到了全桥在基本组合下的内力包络图,通过验算各项应力均满足规范要求,且计算结果与设计结果基本吻合,可知红岩溪特大桥计算模型基本准确。(3)利用红岩溪特大桥裸墩状态、最大悬臂状态和成桥运营状态的有限元模型,考虑了各种施工荷载(如结构自重、风荷载,温度效应、不对称施工荷载、一侧挂篮跌落、不平衡梁段重等)的影响,对该桥进行了施工全过程的稳定性分析。研究表明横桥向风荷载是影响高墩自体稳定性的主要因素;施工至最大悬臂状态时稳定安全系数最低,其中一侧挂篮跌落产生的冲击荷载对结构稳定性造成的影响最大;全桥合拢后稳定性显著提高;在对全桥状态的稳定性分析中发现:横桥向风荷载依然是影响单肢高墩连续刚构桥稳定性的重要因素之一。(4)对影响结构稳定系数的因素进行了参数分析。结果表明考虑几何非线性效应会使结构的稳定性下降,最大悬臂状态下稳定系数下降了4.2%,成桥状态下稳定系数下降了8.8%,成桥状态对非线性效应更加敏感;考查墩身初始缺陷(墩顶偏位、材料缺陷)对单肢高墩连续刚构桥稳定性的影响,发现材料缺陷发生在1/4墩高处时,对结构稳定性影响最不利,稳定系数下降了3.9%;研究还发现在墩高相等的条件下,虽然单肢墩的稳定系数要比双肢墩高了44.6%,但单肢墩的墩顶弯矩值要大得多,将红岩溪特大桥的主墩改换成双肢薄壁型式后,经计算稳定性仍满足规范要求;全桥状态下的稳定性随着两主墩高差的减少而降低,主墩墩顶弯矩也随之减小,其中双肢墩比单肢墩对主墩高差的变化更加敏感;单肢墩施工至30m~50m的范围时稳定系数下降较快,当墩高超过60m后变化速率降低,同时墩体的稳定性随壁厚的加大而增大,而增大速率随着壁厚增大而逐渐放缓。
[Abstract]:Continuous rigid frame bridge is a composite system of pier and beam consolidation, which combines the advantages of continuous beam bridge and T-shaped rigid frame bridge, and is widely used in the construction of bridges in China.At present, the research on the construction process and stability of long-span continuous rigid frame bridge has been deeply studied at home and abroad, but most of the literature researches are aimed at the two-leg thin-walled high-pier continuous rigid frame bridge.There are few researches on the stability of single-leg thin-walled high-pier continuous rigid frame bridge, which has its own characteristics compared with double-legged high-pier, so the stability of single-leg thin-walled high-pier continuous rigid frame bridge is studied.It has certain engineering value and research significance.Based on the Hongyan River continuous rigid frame Bridge on Longyong Expressway in Xiangxi, Hunan Province, this paper studies the cantilever construction process and the stability of the completed state of the continuous rigid frame bridge with single high pier.The main research work and results are as follows: (1) the development history and research status of continuous rigid frame bridges at home and abroad are described, and the basic theory of structural stability research is briefly introduced.Using finite element software Midas/Civil, the calculation model of Hongyan River super large continuous rigid frame bridge is established, and its static analysis is carried out, and the internal force envelope diagram of the whole bridge under the basic combination is obtained.By checking and calculating all the stresses meet the requirements of the code, and the calculation results are basically consistent with the design results, it can be seen that the calculation model of Hongyan River Bridge is basically accurate. 3) the state of bare pier of Hongyan River Bridge is used.The finite element model of the maximum cantilever state and the operation state of the bridge takes into account the effects of various construction loads (such as weight of the structure, wind load, temperature effect, asymmetric construction load, drop of the basket on one side, weight of the unbalanced section of the beam, etc.).The stability of the bridge during construction is analyzed.The results show that the wind load is the main factor that affects the stability of the high pier, the stability safety factor is the lowest in the construction to the maximum cantilever state, and the impact load caused by the drop of one hanging basket has the greatest influence on the stability of the structure.The stability of the whole bridge was improved significantly after closure.In the analysis of the stability of the whole bridge, it is found that the wind load of the transverse bridge is still one of the important factors affecting the stability of the continuous rigid frame bridge with single pier.The results show that considering geometric nonlinear effect, the stability of the structure will be decreased, the stability coefficient of the bridge will decrease by 4.2 in the maximum cantilever state, and the stability coefficient in the bridge will be decreased by 8.8 in the bridge state, and the bridge state will be more sensitive to the nonlinear effect.The influence of initial defect of pier (pier top deviation, material defect) on the stability of single pier continuous rigid frame bridge with high pier is investigated. It is found that when the material defect occurs at the height of 1 / 4 piers, it is most disadvantageous to the stability of the structure.The stability coefficient decreased by 3.9. The study also found that, under the condition of equal pier height, the stability coefficient of single pier is 44.6 higher than that of double pier, but the moment of pier top of single leg pier is much larger. After the main pier of Hongyan River super bridge is changed into two-legged thin-walled type,The stability of the whole bridge decreases with the decrease of the height difference between the two main piers and the bending moment of the top of the main piers decreases, and the double pier is more sensitive to the variation of the height difference of the main piers than the single pier.The stability coefficient of single pier decreases rapidly when it reaches the range of 30m~50m. When the height of pier exceeds 60m, the stability of pier decreases, and the stability of pier increases with the increase of wall thickness, and the increasing rate slows down with the increase of wall thickness.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.4;U448.23

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