超大跨度部分地锚式斜拉桥抗风性能研究

发布时间：2018-01-14 21:03

本文关键词：超大跨度部分地锚式斜拉桥抗风性能研究　出处：《浙江工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：为适应21世纪我国公路交通建设的需要,斜拉桥的跨径日趋增长,尤其是苏通长江大桥的建成,标志着超千米斜拉桥的新时代的到来。跨径越长,斜拉桥的结构刚度越低,致使斜拉桥抗风稳定性成为影响其设计和建设的关键问题。为探索超千米斜拉桥适宜的结构体系,论文以当前备受关注的部分地锚式斜拉桥设计概念为着手,对主跨1400m的部分地锚式斜拉桥设计方案进行结构动力特性、空气静力和动力稳定性等方面的详细分析和探究,从抗风性能角度探讨了部分地锚式斜拉桥设计概念用于超千米跨度桥梁的适用性及其适宜的结构体系,研究成果对超千米斜拉桥的抗风设计具有良好的指导意义。首先,采用Midas/Civil和大跨度桥梁三维非线性抗风稳定性分析程序,对主跨1400米的部分地锚式斜拉桥进行结构动力特性、空气静力和动力稳定性进行分析,在此基础上与同等跨径的自锚式斜拉桥和悬索桥(江阴大桥)进行对比分析,指出部分地锚式斜拉桥在结构动力特性、空气静力和动力稳定性方面更具有优势。其次,对部分地锚式斜拉桥的主要设计参数包括地锚段的长度、辅助墩个数、主梁高度、主梁宽度、桥塔高跨比等对部分地锚式斜拉桥结构动力特性、空气静力和空气动力稳定性的影响进行了分析研究,提出了关键设计参数及其合理取值。最后,开展了部分地锚式斜拉桥施工过程的抗风稳定性分析。研究结果表明:1)边跨部分斜拉索采用地锚方式后,斜拉桥结构的整体刚度增强,结构的自振频率增大,结构的空气静力和动力稳定性因而增强,从抗风性能而言,部分地锚式斜拉桥更适宜采用于千米以上主跨的斜拉桥。2)部分地锚式超大跨度斜拉桥在地锚段长度增加、梁高增大、梁宽增加、边跨增设辅助墩、高跨比加大等情况下,可以获得比较好的空气静力和动力稳定性。3)超大跨度斜拉桥随着主梁拼装长度的增大,结构的竖弯频率变化不大,但结构的侧弯和扭转频率则明显下降,同时出现较强的侧弯和扭转耦合,结构的抗风稳定性因而显著降低。总体上看,施工过程结构的抗风失稳临界风速都比较高,超千米跨度的斜拉桥施工期具有良好的抗风稳定性。
[Abstract]:In order to meet the needs of highway traffic construction in 21th century, the span of cable-stayed bridge is increasing day by day, especially the completion of Sutong Yangtze River Bridge, which marks the arrival of a new era of cable-stayed bridge with more than one kilometer. The longer the span is, the longer the span is. The lower the structural stiffness of cable-stayed bridge is, the more the stability of cable-stayed bridge against wind becomes the key problem to affect the design and construction of cable-stayed bridge. Based on the design concept of partial ground anchor cable-stayed bridge which has been paid much attention to at present, the structural dynamic characteristics of the design scheme of partial ground anchor cable-stayed bridge with main span of 1400m are carried out in this paper. Based on the detailed analysis and exploration of air static and dynamic stability, the applicability of the design concept of partial ground anchor cable-stayed bridge and its suitable structure system for super-kilometer span bridges are discussed from the point of view of wind resistance. The research results have a good guiding significance for the wind resistance design of the super kilometer cable-stayed bridge. Firstly, the Midas/Civil and the three-dimensional nonlinear wind stability analysis program of the long-span bridge are adopted. The structural dynamic characteristics, air static and dynamic stability of partial ground anchor cable-stayed bridge with 1400m main span are analyzed. On the basis of the comparison with the self-anchored cable-stayed bridge and suspension bridge (Jiangyin Bridge) with the same span, it is pointed out that some ground-anchored cable-stayed bridges have dynamic characteristics in the structure. Secondly, the main design parameters of partial ground anchor cable-stayed bridge include the length of ground anchor section, the number of auxiliary piers, the height of main beam and the width of main beam. The effects of tower height to span ratio on the dynamic characteristics, air static and aerodynamic stability of some ground anchor cable-stayed bridges are analyzed, and the key design parameters and their reasonable values are put forward. The wind stability analysis of partial ground anchor cable-stayed bridge during construction is carried out. The results show that the overall stiffness of cable-stayed bridge structure is enhanced after the partial stay cable of the side span of 1: 1) adopts the ground anchor mode. With the increase of the natural frequency of the structure, the air static and dynamic stability of the structure is enhanced. Partial ground anchor cable-stayed bridge is more suitable for cable-stayed bridge with main span of more than km. 2) partial ground anchor type super-span cable-stayed bridge increases in length of anchor section, beam height increases, beam width increases, side span adds auxiliary pier. Under the condition of increasing the ratio of height to span, a relatively good static and dynamic stability of air can be obtained. 3) the frequency of vertical bending of long-span cable-stayed bridge with large span increases with the increase of the assembly length of the main beam, and the frequency of vertical bending of the bridge does not change much. However, the frequency of lateral bending and torsion of the structure is obviously decreased, and there is a strong coupling of lateral bending and torsion at the same time, so the stability of the structure against wind is reduced significantly. The critical wind speed of the construction process structure is relatively high, and the cable-stayed bridge with a span of more than one kilometer has good wind-resistant stability during the construction period.
【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441;U448.27

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