山区桥梁柱式墩计算长度系数、合理尺寸及配筋研究

发布时间：2018-04-03 08:13

本文选题：柱式墩　切入点：计算长度系数　出处：《长安大学》2015年硕士论文

【摘要】：随着我国公路建设模式的转变,BT或PPP项目愈来愈多,而成本控制便成为高速公路建设方重点考虑的问题。特别对于山区高速公路,装配式桥梁成为缩短工期、节省投资的首选,那么柱式墩便随之应用。关于常规跨径下柱式墩的计算长度系数、合理尺寸及配筋成为当下山区高速设计的关键问题。本文以某山区高速公路装配式桥梁为依托工程,利用能量法及有限元方法对25m~40m高墩进行了计算长度系数和截面合理尺寸及配筋研究,取得的主要研究成果如下:利用能量法推导了柱式墩一阶失稳临界力的计算式,通过欧拉公式换算即可得到其计算长度系数。其边界条件包括裸墩与两端弹性约束的柱式墩,与04规范中理想边界约束条件下计算长度相比较,本文得到的计算公式能够满足工程要求。利用有限元程序对25m~40m高墩在给定地质条件下的计算长度系数进行了系统分析,通过大量计算分别给出了裸墩阶段、盖梁连接阶段、施工架梁阶段及成桥阶段四种工况下的计算结果。从分布规律可知:在分析桥墩的计算长度时,可不考虑钢筋对截面刚度的修正;各个桥墩在施工状态计算长度最大、墩梁非固结的成桥状态次之、墩梁固结的成桥状态最小,这说明边界条件对高墩的影响较大。偏安全地考虑计算长度系数对设计的影响,实际应用时建议取表4-4-7中的较大值。利用有限元程序对某山区高速特定地质条件下25m~40m高墩施工阶段及成桥状态钢筋应力、裂缝宽度及强度进行了分析。在给定的地质条件下,成桥状态各个桥墩强度及裂缝验算均能满足规范要求,且有一定的安全储备。施工阶段为控制阶段,考虑两种施工工况进行分析。由计算结果得到建议值:25m高墩,墩径为1.8m,配筋为42φ28;35m高墩,墩径为2.0m,配筋为42φ32;40m高墩,墩径为2.2m,配筋为52φ32。本文的研究结果可为山区桥梁柱式墩的设计提高参考。
[Abstract]:With the change of highway construction mode in our country, there are more and more BT or PPP projects, and cost control has become the focus of highway construction.Especially for mountain highway, the prefabricated bridge becomes the first choice to shorten the time limit and save investment, then the column pier will be applied.The calculation length coefficient, reasonable size and reinforcement of the column piers with conventional span are the key problems in the high speed design of mountainous area at present.In this paper, based on the prefabricated bridge of a mountain highway, the calculation length coefficient, the reasonable size of section and the reinforcement of 25m~40m high pier are studied by energy method and finite element method.The main research results are as follows: by using the energy method, the formula for calculating the critical force of the first order instability of the column pier is derived, and the calculated length coefficient can be obtained by the conversion of the Euler formula.The boundary conditions include bare piers and cylindrical piers with elastic constraints at both ends. Compared with the calculated length under the ideal boundary constraint conditions in Code 04, the formulas obtained in this paper can meet the engineering requirements.The calculated length coefficients of 25m~40m high piers under given geological conditions are systematically analyzed by using finite element program. Through a large number of calculations, the stage of bare pier and the connecting stage of cover beam are given respectively.The results of calculation under four working conditions in the stage of construction beam erection and the stage of bridge completion.From the distribution law, we can know that in analyzing the calculated length of the pier, we can not consider the modification of the section stiffness of the steel bar, the calculated length of each pier is the largest in the construction state, the second is the unconsolidated state of the pier beam, and the least is the consolidation state of the pier beam.This indicates that the boundary condition has a great influence on the high pier.Considering the influence of calculating the length coefficient on the design, it is suggested that the larger values in Table 4-4-7 be taken into account in practical application.The stress, crack width and strength of steel bar in the construction stage of 25m~40m high pier and the state of bridge are analyzed by using finite element program under high speed and special geological conditions in a mountain area.Under the given geological conditions, the strength and crack checking of each pier in the state of the bridge can meet the requirements of the code, and there is a certain safety reserve.The construction stage is the control stage, two construction conditions are considered for analysis.According to the calculated results, the suggested value is: 25 m high pier, 1.8 m diameter, 42 蠁 2835 m high pier, 2.0 m diameter, 42 蠁 32 ~ 40 m high pier, 2.2 m diameter and 52 蠁 32 m high pier.The results of this paper can be used as a reference for the design of bridge column pier in mountainous area.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U443.22

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