【作者】 冼耀强；

【导师】 刘伯权；

【作者基本信息】 长安大学 ， 结构工程， 2013， 博士

【摘要】 轮辐式索膜结构具有质量轻、受力合理、跨越跨度大等优点。该结构由内环索、径向索（脊索、谷索）和压环等构件组成，索系预应力水平及应力分布对整个结构的刚度和受力性能起着至关重要的作用。由于施工偏差、荷载及环境等因素的影响，会导致拉索应力分布不均匀、预应力松弛、连接节点锈蚀等损伤，从而导致结构的受力性能发生明显变化，在地震、飓风等偶然荷载作用下产生潜在的破坏危险。因此，对该类结构开展损伤情况下的动力性能研究十分必要。论文以世纪莲体育中心为背景，通过定性模型试验测试、有限元模拟分析等手段，对轮辐式索膜结构损伤情况下的风致振动、抗震性能和抗倒塌性能进行深入研究，取得了以下几个方面的创新性研究成果：（1）在风洞试验测试基础上，根据逆傅立叶变换技术和频率双索引概念，在谐波合成法的基础上，借助Matlab程序，构造本结构120个节点的脉动风速时程，通过ANSYS有限元程序建立结构的有限元模型，将构造的脉动风速时程施加于结构模型上，分析索松弛损伤情况下结构的风致振动情况。得到了风荷载作用下结构动力反应的基本规律以及损伤情况下结构的敏感风向角（63°和135°风向角）；得到了结构整体动力放大系数的分布规律，认为由风洞试验确定的压力分布系数和风振系数宜乘以结构损伤动力调整系数（取值为1.1），以防止索系预应力松弛或分布不均匀带来的结构动力效应放大，同时给出了结构损伤情况下动力放大系数计算公式。（2）在以上有限元模型基础上，分析了轮辐式索膜结构的动力特性和损伤情况下的抗震性能。结果表明：该结构自振频率较低，频谱集中，频率跳跃现象不明显，结构动力特性复杂，且结构模态质量参与系数与考虑的振型阶数有关；为保证各方向的模态质量参与系数达到90%以上，建议反应谱分析时，其振型取到140阶以上；不同类型地震波作用下本结构的地震反应差别不大，地震分析时可考虑只采用一种地震波进行，但不同方向及多维组合作用对结构的危害主次不明显，应受到同样的关注；索松弛情况下，设计地震作用的内力和位移反应均有可能大于本地区设计风荷载作用下结构的反应，结构设计时应分别进行整体结构地震作用和风荷载作用下的内力分析。（3）按1：60的缩尺比例制作定性模型，进行静力性能试验和数值分析，得到了结构损伤情况下的力学反应和响应规律。分析表明：索松弛对结构的整体刚度和屈服荷载影响较小，但对结构的极限荷载和耗能能力影响较大；压环、腹杆等的刚度对结构的极限荷载和耗能能力影响较大，通过拟静力分析，得到了此类结构上压环、腹杆、下压环、柱之间的合理刚度比：1:1.2:1.3:4.8。（4）对定性模型进行动力损伤测试，并对原型结构进行抗倒塌数值分析，研究了局部索破坏对结构性能的影响。分析表明：动力测试设备无法精确灵敏地捕捉结构密集的频率，通过动力特性测试来监测本结构损伤、判断结构损伤程度和损伤部位非常困难；轮辐式索膜结构主要构件的重要性由小到大依次为悬挂索、腹杆、下压环、上压环、墩柱、分叉索、脊索、谷索、内环索；重要构件断裂造成的破坏程度由轻到重依次为一根谷索断裂、一根脊索断裂、两根相邻谷索断裂、两根相邻脊索断裂、墩柱断裂、两根相邻索断裂、三根相邻索断裂、内环索断裂；结构具有较好的抗连续倒塌能力，重要杆件裂后，能将其承担的荷载迅速传递给相邻构件，从而较好地将坍塌部分限制在有限的区域内；通过采用双索体系、分区域设计和多柱式墩可提高该结构的抗倒塌能力。更多还原

【Abstract】 Wheel-spoke cable-membrane structures have the advantages of light quality, reasonableforce and increasing the span etc, which is composed of the inside pull cables, radial cables,and external pressure rings. Prestressing force level of cables and its distribution plays a vitalrole in the system stiffness and performance. Because of the effect of construction errors,external loads and environmental factors, the cables are likely to be led to the relaxation ofprestressing force, unevenly distributed level stress, and the corrosion on the surface ofcables’ joints. The structure’s behavior will be changed significantly and potential danger maybe caused under Accidental loads, such as earthquake, cyclone, and so on. Therefore, it’s verynecessary to carry out the research of dynamic performance for these damaged structures.Engineering background with Century Lotus Stadium, based on experimental test ofqualitative model and finite element analysis, wind-induced vibration, seismic performance,and collapse-resistant performance of Wheel-spoke cable-membrane structure were subjectedto intensive studies when it was damaged. The following new results were obtained.(1) Based on wind tunnel tests, according to inverse Fourier Transform, and the conceptof frequency double index, and harmonic synthesis method, time history of turbulent windspeed of120joints of the structure were gained by using Matlab program. And then, adoptingANSYS program, wind-induced vibration of the structure were analyzed under these timehistory of turbulent wind speed when prestressing force of the structure’s cables were slacked.The fundamental law of the dynamic response and the sensitive wind direction of the structure,63°angle and135°angle, were gained under wind loads when the structure was damaged.The distribution law of the dynamic magnification factor of the whole structure was obtained.To deter the dynamic amplifying caused by the relaxation of prestressing force or unevenlydistributed level stress of cable system, the pressure distribution coefficient and the winddynamic coefficient gained from wind tunnel tests should be multiplied by adjustingcoefficient of structure’s dynamic damage, equaling1.1. The calculation method of thedynamic coefficient was proposed.(2) Based on the above FEM model, the structure’s dynamic characteristics and itsseismic performance were analyzed. The results show that natural frequencies of the structureare all lower and concentrate in a small range, and its jumping phenomenon isn’t in evidence.Its dynamic characteristics are very complicated. The mode mass participating coefficient isrelated to the mode order. To ensure that the mode mass participating coefficient is not less than90%, the contribution of the former140modes should be considered when the analysisof response spectrum is done. The seismic responses have only a little difference underdifferent types of seismic waves. So we should only calculate one type seismic waves inseismic analysis. Because the harming degree of the seismic loading to the structure is notsimilar when the directions of the earthquake waves are different, the effects of the waves’direction and their combination should be considered. Because the structure’s internal forceand displacement are bigger under designing seismic loads than under designing wind loadswhen the prestressing force of the cable system is released, the internal force should berespectively calculated under seismic loads and wind loads.(3) The qualitative model was made with1:60scales. And then, its static testing andnumerical analysis were done. Mechanics responses and its law were obtained when themodel was damaged. The results shows that the relaxation of prestressing force of cablesystem has only a low impact on the whole stiffness and yield load, but it has a stronginfluence on the limit load and energy dissipating capacity of the structure. The stiffness ofthe compression ring and the truss web also has a strong influence on the limit load andenergy dissipating capacity of the structure. Based on quasi-static analysis of the model, theappropriate stiffness ratio of the upper compression ring, the truss web, the lower compressionring, and the column was obtained, which was1:1.2:1.3:4.8.(4) Dynamic damage test of the qualitative model was done, and the influence of localcables failure on the whole structure was researched based on the collapse-resistant analysis.The results shows that because of the dense natural frequencies and the low impact of cables’damage on the structure’s frequencies, dynamic test equipments couldn’t collect the densenatural frequencies with neat exactitude. It is very difficulty to watch the structure’s damage,judge the degree of structure’s damage and the damage location by testing the dynamiccharacteristics. The importance degree of main components of structure from the little to thegreat is the hanging cables, the truss web, the lower compression ring, the upper compressionring, the column, the divaricating cable, the upper radial cable, the lower radial cable, and theinside pull cables. The degree of the damage caused by the important members breaking fromthe little to the great is the breaking of one lower radial cable, one upper radial cable, twoneighboring lower radial cables, two neighboring upper radial cables, column, twoneighboring radial cables, three neighboring radial cables, the inside pull cables. The structurehas good collapse-resistant performance. After the breaking of important members, their loadscould be rapidly transferred to the neighboring members. And the collapse range was preferably restricted in limited region. Double cables system, zone-design, and multi-columnstyle pier could improve the collapse-resistant performance of the structure.更多还原