【作者】 王奇；

【导师】 楼文娟； 王亚勇；

【作者基本信息】 浙江大学 ， 结构工程， 2010， 博士

【摘要】 体育场挑篷结构是一种复杂体型建筑结构形式,设计难度大。目前,国内外学者对于挑篷结构的研究主要集中在风荷载响应及人群荷载引起的楼面振动上,而对于其在地震作用下的响应研究略显不足。本文以济南奥林匹克体育中心体育场看台为研究背景,通过地震模拟振动台试验和精细的结构分析,对挑篷结构的抗震性能进行了深入的研究。通过设置位移型软钢阻尼器(HADAS)对结构进行耗能减震控制,有效地减少了结构的地震响应。对济南奥林匹克中心体育场部分主体结构1/20模型进行模拟地震振动台试验,测试了模型结构的动力特性、阻尼比及其在当地多遇、设防、罕遇地震作用下的响应。试验中,着重分析了挑篷结构在竖向地震激励下的响应,通过量测挑篷测点的位移、速度、加速度等参数,揭示了挑篷结构在高位支撑时,其竖向地震作用效应(节点加速度响应)放大多达几倍到十几倍这一重要现象,设计中应注意提高挑篷结构支座的强度要求。对模型结构的有限元理论计算分析,进一步揭示了结构的地震响应规律,与振动台试验结果吻合较好。通过水平向及竖向静力弹塑性分析,揭示了结构产生塑性铰的顺序,改进的能力谱法进一步验证了结构的抗震能力。针对挑篷结构对于竖向地震动敏感的这一特性,建立了多模态组合的竖向静力弹塑性分析方法,特别提出了在竖向静力弹塑性分析时考虑高阶模态的贡献,计算结果显示,若采用传统的单阶竖向模态加载模式,会使计算结果明显偏于不安全,因此建议对挑篷这类结构进行竖向静力弹塑性分析时,宜采用多模态组合的加载模式。将多维虚拟激励法进一步应用于挑篷结构的多维地震随机响应分析中。详细介绍了多维地面运动功率谱密度函数模型及其参数,给出了均值响应和峰值响应的评估方法,比较了挑篷结构在单向和多向地震动输入下的关键节点位移反应,计算结果表明,多维地震动会明显加大结构的响应。将虚拟激励法的计算结果与时程法的进行比较,两者的计算结果吻合较好。多维虚拟激励法作为一种高效的随机振动分析方法,为对大型体育场挑篷这类结构进行多维地震随机振动分析提供了有效的途径。对施加位移型软钢阻尼器的模型结构进行弹塑性时程分析,比较设置前后结构的塑性反应。结果显示,无论是从钢结构挑篷杆件塑性铰的出现情况,还是从杆件的地震响应,以及不同位置的阻尼器滞回曲线,都可以看出阻尼器有效地吸收了一部分地震动传给结构的能量,减少了其地震响应。通过模拟分析,验证了位移型软钢阻尼器对于挑篷这类结构的耗能减震的效果,为今后同类结构的耗能减震设计提供一定的参考依据。更多还原

【Abstract】 Stadium structure with cantilever roof is so complicated that it’s hard to be designed. At present, home and abroad scholars pay more attention to the response of cantilever roof structure under the wind loads and the vibration on the floor which caused by crowd moving human loads, and the seismic responses are little to be concerned relatively. Based on the shaking table experiment of Jinan Olympic Center and finite element analysis, the seismic performances of cantilever roof structure were deeply studied. Attempt of setting the displacement-type mild steel damper (HADAS) on the structure, the responses under seismic excitation were controlled, and it effectively reduced the seismic response.A shaking table test of a 1/20 scale model of the Jinan Olympic Center was carried out. The model’s dynamic properties, damping ratio and seismic responses under different earthquake levels were studied. During the test, the vertical seismic responses of cantilever roof structure were specially analysised. By measuring the key point’s displacement、velocity and acceleration responses, the phenomenon that the seismic effects on cantilever roof structure which with high supports were amplified over 10 times in the vertical direction was revealed, and it guide the design to focus on the improvement of the strength requirement of cantilever roof structure’s supports.Finite element analysis further revealed the laws of the seismic responses, and they were in good agreement with the shaking table test results. A sequence of generating hinges was studied by horizontal and vertical elasto-plastic analysis, and the structural seismic performance was further evaluated by capacity spectrum method. Because the cantilever roof structure was sensitive for the vertical ground motion, the vertical multi-model combination nonlinear static analysis method had been established. The contribution of higher modes was specifically taken into account, and the results show that the use of traditional single-modal loading mode method will obviously lead to unsafe results. Therefore, the multi-modal method is recommended for the vertical static elasto-plastic analysis of canopy structure.The pseudo excitation method was further improved and used for multi-dimensional random seismic analysis of the cantilever roof structure. Theoretical formulations for multi-dimensional pseudo excitation algorithm were derived. A method of evaluating average peak responses was recommended. Seismic random models and parameters under multiple seismic ground motions were detailed introduced. The displacement responses of key nodes under single dimension and multiple dimensions were compared by calculating. The structure response under multi-dimension seismic input would be significantly magnified. The results of pseudo excitation method and the time history analysis were compared to verify the accuracy of multi-dimensional pseudo excitation method, and they were in good agreement. Multi-dimensional pseudo excitation method as an efficient random vibration analysis method provides an effective way to the field of random vibration analysis of large-scale stadium structure with cantilever roof.Nonlinear time history analysis on the modal structure with displacement-type mild steel damper was carried out. Compared with the plastic responses results of the two structures (with and without damper), no matter the appearance of plastic hinges, or the seismic response of members, even the hysteretic curve of dampers on different positions, all indicate that dampers effectively absorbed part of ground motion energy which passed to the structure, and reduced its seismic response. By simulation analysis, the energy dissipation effect of cantilever roof structural with displacement-type mild steel damper were verified, and it provide a reference for the future design of energy dissipation wiith similar structures.更多还原