不良地质条件下钢桁架加固双曲拱桥的理论与试验研究
发布时间：2018-09-17 13:34
【摘要】：我国大部分双曲拱桥建于上世纪六、七十年代，由于设计荷载标准低、施工水平低，在长期超负荷运营下损伤病害日益加剧；双曲拱桥对于不良地质条件的适应性较差，地基沉降及基础滑移等病害对双曲拱桥的拱脚截面造成严重损害；同时，在我国温差较大的东北地区，温度应力更加剧了这一病害状况，导致双曲拱桥实际工作状态发生改变。随着双曲拱桥服役年限增长，且面临交通流量和车载逐步加大的风险，对双曲拱桥进行维修、加固，使其满足现有交通正常运营要求，成为亟待解决的问题。本文从不良地质条件下双曲拱桥损伤后拱肋的实际受力状况出发，针对拱脚已发生微小转动，形成半固结连接的真实情况，提出在既有的拱肋底部采取钢桁架进行加固的方法，并通过加固原理和计算理论分析、拱肋模型试验、数值模拟分析和实际工程现场试验，对该加固方法开展了相关的研究工作，并取得了一定的成果，主要有： （1）查阅了大量的相关资料文献，回顾双曲拱桥在特定历史时期的发展历程，对双曲拱桥的各构件的构造特点、施工技术手段及其加固方法进行了总结，剖析不良地质条件对双曲拱桥的损害机理及病害特点，分析了钢桁架加固双曲拱桥方法的可行性。 （2）对两铰拱的力学性能进行研究，分析指出活荷载弯矩的抵抗能力不足是导致双曲拱拱桥承载能力降低的主要因素；并在此基础上研究分析钢桁架加固两铰双曲拱桥方法的力学原理。 （3）在分析钢桁架加固双曲拱桥结构构件实际受力状况的基础上，提出将原拱肋视作能够承受弯矩的刚性构件，钢桁架的腹杆和下弦杆视为承受轴向力的构件，建立了钢桁架加固双曲拱桥的力学简化模型。通过对钢桁架的几何形状参数的影响因素的分析，提出了钢桁架几何形状设计的合理建议。在力学简化模型的基础上，按照桁梁混合结构的研究思路，提出了钢桁架加固双曲拱桥拱肋的力法计算方法。 （4）运用通用有限元程序ABAQUS对加固前后模型进行非线性分析，结果表明加固后拱肋弯矩降低，拱肋的受力状态更加合理，承载能力提高了2.4倍。 （5）制作了2个拱肋试验模型，分别为未加固拱肋模型和采用钢桁架加固的拱肋模型；并进行跨中集中力加载。从试验现象来看，未加固拱肋模型在跨中出现竖直向上发展的裂缝，接近破坏阶段时，在1/8跨附近出现上部裂缝。采用钢桁架加固后试件跨中裂缝开展明显减小，在混凝土拱肋上部未出现裂缝。 （6）在试验过程中，未加固拱肋在1/8跨处挠度出现先向下发展后向上发展的现象，在1/4跨、3/8跨和跨中处挠度随荷载增加均保持向下发展；钢桁架加固拱肋所有测点位置处挠度均向下发展，两拱肋挠度增长分布情况相同，，跨中挠度增长速度最大，依次向支座方向递减。由数据分析可知，加固后挠度随荷载线性增长状态程度优于未加固拱肋，除1/8跨位置外，其余测点位置处挠度增速均小于未加固拱肋，表明采用钢桁架进行加固后，试件的整体刚度更加匀称，构件整体化程度显著提高。 （7）通过对试验应变数据整理分析可知，采用钢桁架加固后，混凝土拱肋在1/8跨、1/4跨处弯矩大幅降低，截面始终保持受压状态；3/8跨位置处和跨中处下部纵向钢筋拉应变值大幅降低，截面主要承受压力；表明加固后拱肋截面的弯矩减小，受力状态更加合理，采用钢桁架加固后，拱肋的开裂荷载、屈服荷载、极限荷载分别提高2.94倍、2.28倍、2.21倍，试件的承载能力大幅度提高。 （8）对长安大桥采用钢桁架进行加固，并进行了桥梁荷载试验，试验数据表明加固后结构整体受力性能得到显著改善，桥梁结构的承载能力和整体刚度明显提升，达到预期的加固效果；证明钢桁架加固双曲拱桥方法是可行的。
[Abstract]:Most of the double-curved arch bridges in China were built in the 1960s and 1970s. Due to the low design load standard and construction level, the damage of the double-curved arch bridges under long-term overload operation is becoming more and more serious. At the same time, in Northeast China where the temperature difference is large, the temperature stress aggravates the disease, which leads to the change of the actual working state of the double-curved arch bridge. Based on the actual stress condition of damaged arch ribs of double-curved arch bridges under bad geological conditions and the fact that the arch foot has turned slightly to form a semi-consolidated connection, a method of strengthening the existing arch rib bottom with steel truss is proposed in this paper. The arch rib model test, numerical simulation analysis and actual engineering field test have carried out relevant research work on the reinforcement method, and achieved some results, mainly as follows:
(1) Reviewing the development course of the double-curved arch bridge in a specific historical period by consulting a large number of relevant documents, summing up the structural characteristics, construction techniques and reinforcement methods of the components of the double-curved arch bridge, analyzing the damage mechanism and disease characteristics of the double-curved arch bridge caused by bad geological conditions, and analyzing the square of the double-curved arch bridge strengthened by steel truss. The feasibility of the law.
(2) The mechanical properties of two-hinged arch are studied, and it is pointed out that the insufficient resistance to live load moment is the main factor leading to the reduction of the bearing capacity of double-curved arch bridge.
(3) On the basis of analyzing the actual stress state of the structural members of the double-curved arch bridge strengthened with steel truss, the paper puts forward that the original arch rib is regarded as a rigid member which can bear bending moment, and the web bar and the lower chord bar of the steel truss are regarded as members which bear axial force. The simplified mechanical model of the double-curved arch bridge strengthened with steel truss is established. Based on the simplified mechanical model and the research idea of the truss-beam hybrid structure, a force method for calculating the arch ribs of the double-curved arch bridge strengthened by the steel truss is proposed.
(4) The finite element program ABAQUS is used to analyze the non-linear model before and after reinforcement. The results show that the bending moment of the arch rib is reduced, the stress state of the arch rib is more reasonable, and the bearing capacity is increased by 2.4 times.
(5) Two test models of arch ribs were made, which were the unreinforced arch rib model and the steel truss reinforced arch rib model, and were loaded with concentrated force in the middle of the span. The cracks in the mid span of the concrete specimens were significantly reduced, and no cracks appeared on the upper part of the concrete arch ribs.
(6) During the test, the deflection of the unreinforced arch rib develops downward first and then upwards at the 1/8 span, and keeps downward with the increase of load at the 1/4 span, 3/8 span and the middle of the span; the deflection at all measuring points of the arch rib strengthened by steel truss develops downward, and the deflection distribution of the two arch ribs is the same, and the deflection growth rate at the middle of the span is the same. According to the data analysis, the deflection of the strengthened arch rib is better than that of the unreinforced arch rib, except for the 1/8 span position, the deflection of the other measuring points is less than that of the unreinforced arch rib, which indicates that the overall stiffness of the specimens is more symmetrical and the integral degree of the members is more than that of the unreinforced arch rib. Marked improvement.
(7) According to the analysis of the test strain data, the bending moment of concrete arch rib decreases greatly at 1/8 span and 1/4 span, and the section keeps compression state after strengthening with steel truss; the tensile strain value of longitudinal reinforcement decreases greatly at 3/8 span and lower part of midspan, and the section bears pressure mainly; it shows that the bending moment of arch rib section decreases after strengthening. The cracking load, yield load and ultimate load of the arch rib are increased by 2.94 times, 2.28 times and 2.21 times respectively after strengthening with steel truss.
(8) The steel truss is used to reinforce Chang'an Bridge, and the load test of the bridge is carried out. The test data show that the overall mechanical performance of the structure has been significantly improved, the bearing capacity and overall stiffness of the bridge structure have been significantly improved, and the expected reinforcement effect has been achieved.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U445.72
本文编号：2246078
[Abstract]:Most of the double-curved arch bridges in China were built in the 1960s and 1970s. Due to the low design load standard and construction level, the damage of the double-curved arch bridges under long-term overload operation is becoming more and more serious. At the same time, in Northeast China where the temperature difference is large, the temperature stress aggravates the disease, which leads to the change of the actual working state of the double-curved arch bridge. Based on the actual stress condition of damaged arch ribs of double-curved arch bridges under bad geological conditions and the fact that the arch foot has turned slightly to form a semi-consolidated connection, a method of strengthening the existing arch rib bottom with steel truss is proposed in this paper. The arch rib model test, numerical simulation analysis and actual engineering field test have carried out relevant research work on the reinforcement method, and achieved some results, mainly as follows:
(1) Reviewing the development course of the double-curved arch bridge in a specific historical period by consulting a large number of relevant documents, summing up the structural characteristics, construction techniques and reinforcement methods of the components of the double-curved arch bridge, analyzing the damage mechanism and disease characteristics of the double-curved arch bridge caused by bad geological conditions, and analyzing the square of the double-curved arch bridge strengthened by steel truss. The feasibility of the law.
(2) The mechanical properties of two-hinged arch are studied, and it is pointed out that the insufficient resistance to live load moment is the main factor leading to the reduction of the bearing capacity of double-curved arch bridge.
(3) On the basis of analyzing the actual stress state of the structural members of the double-curved arch bridge strengthened with steel truss, the paper puts forward that the original arch rib is regarded as a rigid member which can bear bending moment, and the web bar and the lower chord bar of the steel truss are regarded as members which bear axial force. The simplified mechanical model of the double-curved arch bridge strengthened with steel truss is established. Based on the simplified mechanical model and the research idea of the truss-beam hybrid structure, a force method for calculating the arch ribs of the double-curved arch bridge strengthened by the steel truss is proposed.
(4) The finite element program ABAQUS is used to analyze the non-linear model before and after reinforcement. The results show that the bending moment of the arch rib is reduced, the stress state of the arch rib is more reasonable, and the bearing capacity is increased by 2.4 times.
(5) Two test models of arch ribs were made, which were the unreinforced arch rib model and the steel truss reinforced arch rib model, and were loaded with concentrated force in the middle of the span. The cracks in the mid span of the concrete specimens were significantly reduced, and no cracks appeared on the upper part of the concrete arch ribs.
(6) During the test, the deflection of the unreinforced arch rib develops downward first and then upwards at the 1/8 span, and keeps downward with the increase of load at the 1/4 span, 3/8 span and the middle of the span; the deflection at all measuring points of the arch rib strengthened by steel truss develops downward, and the deflection distribution of the two arch ribs is the same, and the deflection growth rate at the middle of the span is the same. According to the data analysis, the deflection of the strengthened arch rib is better than that of the unreinforced arch rib, except for the 1/8 span position, the deflection of the other measuring points is less than that of the unreinforced arch rib, which indicates that the overall stiffness of the specimens is more symmetrical and the integral degree of the members is more than that of the unreinforced arch rib. Marked improvement.
(7) According to the analysis of the test strain data, the bending moment of concrete arch rib decreases greatly at 1/8 span and 1/4 span, and the section keeps compression state after strengthening with steel truss; the tensile strain value of longitudinal reinforcement decreases greatly at 3/8 span and lower part of midspan, and the section bears pressure mainly; it shows that the bending moment of arch rib section decreases after strengthening. The cracking load, yield load and ultimate load of the arch rib are increased by 2.94 times, 2.28 times and 2.21 times respectively after strengthening with steel truss.
(8) The steel truss is used to reinforce Chang'an Bridge, and the load test of the bridge is carried out. The test data show that the overall mechanical performance of the structure has been significantly improved, the bearing capacity and overall stiffness of the bridge structure have been significantly improved, and the expected reinforcement effect has been achieved.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U445.72
【参考文献】
相关期刊论文 前10条
1 罗苓隆;加大截面加固钢筋混凝土构件的正截面强度计算方法[J];四川建筑科学研究;1989年04期
2 周益云,赵人达,钟明全,王晓阳;大跨度双曲拱桥的静力分析及加固措施[J];四川建筑科学研究;2001年03期
3 江元盛;;钢筋混凝土结构增大截面加固法的几点体会[J];安徽建筑;2008年02期
4 李涛;南京长江大桥公路双曲拱桥桥面整修设计[J];城市道桥与防洪;1997年03期
5 尹健,周士琼,李益进,张松洪;新老混凝土本构关系理论分析研究[J];长沙铁道学院学报;2002年03期
6 蓝宗建，黄兴棣，田安国，田炜;钢筋混凝土围套加固偏心受压柱的试验研究[J];东南大学学报;1994年03期
7 马保国,王迎飞,朱洪波,黄春泉;冬期施工中负温混凝土耐久性设计[J];低温建筑技术;2002年03期
8 李秋博;;混凝土早期收缩、开裂对结构耐久性的影响[J];大众科技;2008年11期
9 孙明山;桥梁检查及病害原因分析[J];湖南交通科技;2001年04期
10 任成志,刘君辉;道县潇水大桥维修加固[J];湖南交通科技;2004年02期
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