既有双曲拱桥检测、评定及加固技术改进研究

发布时间：2018-04-03 17:48

本文选题：双曲拱桥　切入点：检测　出处：《南京工业大学》2015年硕士论文

【摘要】：老旧双曲拱桥由于建造年代久远,维修保养落后,其损坏严重,因此对双曲拱桥进行检测、加固是一项十分重要且有意义的事情。但目前现有的双曲拱桥检测项目和检测方法并不完善,其技术状况评定方法也存在可优化之处,针对拱顶、拱脚正负弯矩过大的双曲拱桥的加固技术研究较少。本文通过理论研究、有限元计算并结合工程实践,对双曲拱桥的检测、评定及加固技术进行了研究：(1)对拱轴线测量及构件混凝土强度检测等提出了改进的检测方法,为双曲拱桥的检测工作提供了依据；(2)双曲拱桥技术状况评定中对拱轴线变形形式没有分类,对变形程度只有定性描述没有定量标准,本文将拱轴线变形分为“M”形和均匀变形两种形式。利用MIDAS-CIVIL建立不同跨径、不同矢跨比的桥梁平面杆系模型,以拱顶变形值为目标参数,分析不同偏离值下拱圈控制截面内力、挠度变化情况。按照内力及挠度变化率相同的原则参考现有评定标准中对构件技术状况的描述,将拱顶偏离值划分为不同的区间,以此区间作为拱轴线变形评定标度的界限,完善了双曲拱桥拱轴线变形评定标准：(3)现有双曲拱桥技术状况评定中对拱脚位移评定标准不够明确,为此本文利用MIDAS-CIVIL建立不同跨径、不同矢跨比的桥梁平面杆系模型,分析不同拱脚位移下,拱圈控制截面内力、挠度、应力及承载力变化情况。并以满足承载力为原则,通过有限元试算与网格曲线图结合确定拱脚位移“限值”。结果表明,在拱脚位移尚未达到“限值”之前,各参数随拱脚位移增加近似呈线性变化,因此,可将拱脚位移“限值”均分为三个区间,作为尚未达到限值的拱脚位移评定标度的界限,完善了双曲拱桥拱脚位移评定标准：(4)针对拱顶正弯矩过大而出现破坏的双曲拱桥,提出了体外预应力加固双曲拱桥拱顶的新方法,优化给出了两种不同的加固形式。基于体外预应力在拱顶产生的负弯矩“抵消”恒载下拱顶正弯矩的原则,理论上推导出了不同布筋形式下预应力筋预拉力值和锚固位置的计算公式。采用有限元软件建立不同跨径、不同矢跨比的平面杆系模型,分析了两种布筋形式下不同预拉力值时拱圈各截面的应力、挠度、承载能力的变化情况。结果表明,拱顶采用体外预应力加固可以很好地“抵消”拱顶正弯矩,降低拱顶下缘拉应力、高拱顶截面承载能力；(5)以贵州省孟彦大桥为实例,采用改进优化后的检测、评定方法对该桥进行检测评定。结果表明,该桥上、下部结构裂缝较多,变形较大损坏严重,评定为四类桥(需加固)。针对该桥拱顶下缘开裂的破坏情况,结合体外预应力加固方法的研究采用直线式体外预应力加固该桥,并进行加固计算和加固效果分析。结果表明,加固减少了拱顶下缘拉应力、提高了拱顶承载力。
[Abstract]:The old double-curved arch bridge is damaged seriously because of its long construction, backward repair and maintenance, so it is very important and meaningful to inspect and strengthen the hyperbolic arch bridge.However, the existing inspection items and detection methods of hyperbolic arch bridge are not perfect, and the evaluation method of its technical condition can also be optimized. There is little research on reinforcement technology of hyperbolic arch bridge with arch roof and too large positive and negative moment of arch foot.In this paper, through theoretical research, finite element calculation and engineering practice, the detection, evaluation and reinforcement technology of hyperbolic arch bridge are studied.This paper provides a basis for the inspection of hyperbolic arch bridge. In the evaluation of the technical condition of hyperbolic arch bridge, there is no classification of deformation form of arch axis, but there is no quantitative standard for qualitative description of deformation degree.In this paper, the arch axis deformation is divided into "M" shape and uniform deformation.In this paper, MIDAS-CIVIL is used to establish a bridge plane bar system model with different span and different ratio of span to span. Taking the deformation value of arch top as the target parameter, the variation of internal force and deflection of arch ring control section under different deviations is analyzed.According to the principle of the same change rate of internal force and deflection, according to the description of the technical condition of the component in the existing evaluation standard, the deviation value of the vault is divided into different intervals, which is used as the limit of the evaluation scale of the deformation of the arch axis.This paper improves the evaluation standard of arch axis deformation of hyperbolic arch bridge: (3) the evaluation standard of arch foot displacement of hyperbolic arch bridge is not clear enough in the current evaluation of the technical condition of hyperbolic arch bridge. In this paper, MIDAS-CIVIL is used to establish the bridge plane bar system model with different span and different rise-span ratio.The variation of internal force, deflection, stress and bearing capacity of arch ring control section under different arch foot displacement is analyzed.Based on the principle of satisfying the bearing capacity, the finite value of arch foot displacement is determined by the combination of finite element test and grid graph.The results show that before the arch foot displacement reaches the "limit value", each parameter changes approximately linearly with the arch foot displacement increase. Therefore, the arch foot displacement "limit value" can be divided into three intervals.As the limit limit of arch foot displacement evaluation scale, the standard of arch foot displacement evaluation of hyperbolic arch bridge is improved.A new method for strengthening the vault of double curved arch bridge with external prestressing is proposed, and two different reinforcement forms are given.Based on the principle of "counteracting" the negative moment produced by external prestressing in the vault under dead load, the formulas for calculating the pretension force and the anchoring position of the prestressed tendons under different reinforcement forms are derived theoretically.The finite element software is used to establish a plane bar system model with different span and different rise-span ratio, and the variation of stress, deflection and bearing capacity of arch ring under different pretension force under two kinds of tendons is analyzed.The results show that the external prestressing reinforcement of the arch roof can "offset" the positive moment of the arch roof, reduce the tensile stress at the lower edge of the vault, and the bearing capacity of the section of the high arch roof can be reduced.) taking the Mengyan Bridge in Guizhou Province as an example, the improved and optimized test is adopted.The bridge was tested and evaluated by the evaluation method.The results show that there are many cracks in the substructure of the bridge, and the deformation is serious, which is assessed as four types of bridges (need to be strengthened).In view of the cracking of the lower edge of the arch roof of the bridge, combined with the study of the external prestressing reinforcement method, the bridge was strengthened with the external prestressing force of the straight line, and the reinforcement calculation and the effect analysis were carried out.The results show that the reinforcement reduces the tensile stress at the lower edge of the arch roof and increases the bearing capacity of the arch roof.
【学位授予单位】：南京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446;U445.72

【相似文献】