【作者】 张玉涛；

【导师】 杜斌；

【作者基本信息】 贵州大学 ， 土木工程， 2019， 硕士

【摘要】 本文以贵州某自锚式悬索桥为研究对象,采用数值模拟与施工监控数据相结合的方式,对该桥施工阶段主缆线形及体系转换等工作进行分析,对该结构静动力特性及设计参数的影响等进行研究,并总结该桥在施工及监控环节中的关键技术,通过上述工作可得出如下结论:1.首先简述了自锚式悬索桥的结构特点及受力方式,对国内外自锚式悬索桥的发展及研究现状进行综述,肯定了自锚式悬索桥在国内的发展前景及结构优势,并对该桥背景等进行介绍;2.对早期悬索桥分析计算常采用的弹性理论、挠度理论和现阶段应用广泛的有限位移及非线性有限元理论进行介绍;对三种计算理论使用时的基本假定进行汇总;分析了早期计算理论在大跨径及复杂悬索桥计算中的误差所在,确定有限位移及非线性有限元理论用于悬索桥计算中的准确性及严谨性;3.根据设计资料及现场情况,对该桥建立完整的有限元模型,并开展了主缆线形找形及参数影响分析、结构体系转换方案研究等工作。通过主缆线形计算可知,传统抛物线法较分段悬链线法及非线性有限元法简单,但误差大,后两种方法结果较接近,精度高,同时证明了非线性有限元程序对该项目进行施工控制具有较高的可行性。对主缆线形参数影响分析时,结构荷载信息对主缆找形有明显影响,需准确统计;在主缆索股架设前,需抽样检测索股出厂参数,保证主缆弾模等参数准确性;温度属高敏感因素,在主缆索股架设过程中要选择温度幅度变化小的时间段作业,并根据实际温度实时调整架设方案。针对结构特点提出四套体系转换方案,并进行论证,最终确定最优方案为从主塔侧向两边对称安装张拉吊索,分析结果表明,该方案成桥吊杆及主缆受力均匀,主缆及主梁线形误差小,安全系数高;4.对该桥进行有限元分析,确立该桥的合理成桥状态,证明该状态下缆梁线形及缆索内力准确、精度高,适用于后期进行静动力分析工作。分析了温度、移动荷载、静风荷载等对结构的各构件产生的影响,结果显示温度对缆索线形影响较大,移动荷载作用对主跨主梁线形影响较大,所设静风荷载对塔梁固结形式的混凝土结构影响较小。主跨主缆跨矢比对结构静力行为影响较小,而主缆弹模及混凝土收缩徐变对结构受力影响较大,需合理选取设计材料参数并加强混凝土结构养护措施。单根吊索破断对结构安全性影响较小,证明了该结构具有足够的刚度和强度;分析了该桥自振特性,结果显示一阶自振频率为0.816Hz,且跨径小、塔梁固结,该桥具有较大的刚度;该桥的地锚式较自锚式自振频率略高,刚度更大;主梁竖振及主缆横振出现较多,且扭转模态靠后,证明抗风稳定性较好;缆索、塔梁刚度的增大直接导致全桥刚度的增大;主梁恒载集度增大,导致结构自振频率减小;5.对该桥在施工阶段涉及到的关键环节以及施工监控重要工作进行阐述,结合项目施工现场收集到的实测数据,对该桥施工环节进行评价,该桥主塔施工质量较好,主梁及主缆线形与设计状态吻合,吊索张拉及主索鞍顶推施工较精确可控,该桥的施工及监控工作可为同类桥梁建设提供参考。更多还原

【Abstract】 In this paper,a self-anchored suspension bridge in Guizhou Province is taken as the research object.By combining numerical simulation with construction monitoring data,the static and dynamic characteristics of the bridge and the influence of design parameters are studied as follows:(1)This paper briefly describes the structural characteristics and stress modes of self-anchored suspension bridges,summarizes the development and research status of self-anchored suspension bridges at home and abroad,affirms the development prospects and structural advantages of self-anchored suspension bridges in China,and introduces the background of the bridge.(2)The elastic theory,deflection theory and finite displacement and non-linear finite element theory commonly used in the analysis and calculation of early suspension bridges are introduced.Summarize the basic assumptions in the use of three computational theories.The errors of early calculation theory in calculation of long span and complex suspension bridges are analyzed.The accuracy and rigor of finite displacement and non-linear finite element theory in calculation of suspension bridges are affirmed.Finally,the non-linear influencing factors of self-anchored suspension bridges are briefly introduced.(3)According to the design data and site conditions,the complete finite element model of the bridge is established,and the main cable shape finding,parameter impact analysis,structural system transformation scheme research are carried out.The calculation of main cable shape finding shows that the traditional parabola method is simpler than the piecewise catenary method and the nonlinear finite element method,but the error is large.The results of the latter two methods are close and the precision is high.At the same time,it proves that the non-linear finite element software Madis/Civil has a high feasibility to control the construction of this project.When the influence of structural load information on main cable shape parameters is analyzed,the main cable shape finding is obviously affected by structural load information,which needs to be accurately counted.Before erecting the main cable strand,the factory parameters of the main cable strand should be sampled to ensure the accuracy of the parameters such as upsetting die of the main cable.Temperature is a highly sensitive factor.During the erection of the main cable strand,the range of temperature variation should be controlled and the erection scheme should be adjusted in real time according to the actual temperature.According to the structural characteristics,four systems conversion schemes are put forward and demonstrated.Finally,the optimum scheme is to install tensioned suspension cable symmetrically from the side to both sides of the main tower.The analysis results show that the scheme has high feasibility and safety factor,uniform force acting on the completed suspension rod and main cable,and small alignment error of the main cable and girder.(4)The finite element analysis of the bridge is carried out to determine the reasonable completedstate of the bridge.It is proved that the cable girder alignment and internal force of the cable under this state are accurate and accurate,and are suitable for the static and dynamic analysis work in the later stage.The influence of temperature,moving load and static wind load on the static behavior of the structure is analyzed.The results show that temperature has a great influence on the cable alignment,moving load has a great influence on the main span girder alignment,and static wind load has a little influence on the consolidated concrete structure of the tower girder.The rise-span ratio of main span and main cable has little influence on the static behavior of structure,while the elastic modulus of main cable and the shrinkage and creep of concrete have great influence on the structural stress.It is necessary to select reasonable design material parameters and strengthen the maintenance measures of concrete structure.The breakage of a single sling has little influence on the safety of the structure,and the whole structure will have adverse effects on the resistance,which proves that the structure has sufficient stiffness and strength.The natural vibration characteristics of the bridge are analyzed.The results show that the first-order natural frequency is0.816 Hz,the span is small,the tower and beam are consolidated,and the bridge has larger stiffness.The ground anchor type of the bridge has a slightly higher natural frequency and stiffness than the self-anchored type.Vertical vibration of girder and transverse vibration of main cable appear more frequently,and torsional mode is backward,which proves that the stability of wind resistance is better.The increase of stiffness of cable and tower girder directly leads to the increase of stiffness of the whole bridge,the increase of dead load concentration,the increase of dead load concentration and the decrease of natural vibration frequency of the structure.(5)This paper expounds the key links involved in the construction stage of the bridge and the important work of construction monitoring,evaluates the construction links of the bridge based on the measured data collected from the construction site of the project.The construction quality of the main tower of the bridge is better,the main girder and cable shape are in good agreement with the design state,the construction of suspension tension and main cable saddle is more precise and controllable,and the construction and monitoring work of the bridge can be done.It provides a reference for the construction of similar bridges.更多还原