【作者】 岳茂光；

【导师】 李宏男； 王亚勇； 王东升；

【作者基本信息】 大连理工大学 ， 防灾减灾工程与防护工程， 2009， 博士

【摘要】 由于城市建设规模的不断扩展及土地资源的减少,在存在液化、震陷及岸坡失稳等抗震不利地段亦开始大量修建高层建筑,场地非线性及稳定性对结构抗震性能影响显著。本文研究目的是在现有抗震规范“三水准二阶段”设计方法基础上,提升基于性能抗震设计理论的实用性及可实现性,并纳入场地非线性、稳定性影响因素,以服务于工程实践。主要包括以下内容:1.在建立的小型工程用强震数据库基础上提出了考虑高阶振型影响的输入地震波的选波原则,即以规范谱为基准,采用平台段反应谱的均值误差和对结构影响较大的前几阶周期附近反应谱的加权误差的双控指标进行选波。提出了完全非平稳多点人工波的模拟方法,强度非平稳特性通过传统的包络函数来考虑,频率非平稳特性通过相位差谱来体现,并且针对Clough-Penzien功率谱密度函数建议了模拟多点地震动的峰值因子的取值。2.对多级性能设计目标进行了讨论并特别就“中震不屈服”和“中震弹性”提出了若干建议。以一个多层框架结构和一个高层框架剪力墙结构为例,对小震丙类、小震乙类、中震不屈服和中震弹性四个性能目标进行了研究。工程量分析和增量动力分析表明,6度区按中震设计并不能明显提高结构的抗倒塌能力;7度和8度按中震性能目标设计的结构的抗倒塌能力会明显提高,但是工程量增加显著,所以设计时应谨慎,否则可能会无法实际实现。最后,用汶川强震记录分析了汶川地区按7度(震前)和8度(震后)抗震设防设计的框架结构的抗倒塌能力。3.提出了场地-支护结构-高层建筑抗震设计的三水准性能目标准则并具体实现,包括场地的滑移和震陷的判断标准、支护结构的抗震性能目标和支护结构对高层建筑整体稳定性的影响分析。福建某建设场地的抗震稳定分析表明,小震下场地只发生轻微震陷,但不会滑移;中震下场地会发生中等震陷,堤岸附近土体会产生一定滑移;大震下场地会发生严重震陷和滑移,将对结构产生较严重影响。支护结构的地震内力分析表明双排支护桩能够满足小震不开裂、中震不屈服、大震不坏的性能目标。4.利用生成的多点人工波分析了基岩多点激励下场地和支护结构的抗震性能。分析表明,大多数情况下多点激励会降低地表的地震动参数,减小地表的水平相对位移和竖向震陷位移,减小支护桩的地震内力反应等,但是也会放大某些地震反应,比如堤岸挡墙的最大弯矩反应和第二排支护桩的桩顶水平相对位移等。5.研究了双向地震作用下场地非线性对上部高层结构抗震性能的影响。分析表明对于高层框剪结构,考虑场地非线性反应的影响后,体系的绝对加速度、层间位移,以及构件的地震内力反应在不同的楼层均有放大现象,因此折减有时是偏危险的。场地非线性对构件不同方向地震反应的影响不同,双向地震动作用下,各楼层的层间位移、绝对加速度、构件内力的折减系数也并不相同。因此,规范中只采用单一的折减系数亦不太合理。更多还原

【Abstract】 As construction scope developing and land resources diminishing continuously in city, mass of high-rise buildings are constructed in disadvantage area where exist liquefaction, subsidence and destabilization slop.The field nonlinearity and stabilization has significant influences on structural seismic performance.Based on the design concept of ’three-level and two-stage’,the research scope of this paper is focus on upgrading the practicability and realization of performance-based seismic design theory.The other influences factors,such as field nonlinearity and slope stabilization,are also considered.The primary contents include:1.A new wave selection method in time history analysis is proposed based on the small database of strong ground motions,in which the influence of higher vibration modes can be considered in structure design.The principle of the method is both the error at platform segment and weighted error near each period between standard spectra and response spectra of the waves are controlled in a specified scope.On the other hand,Simulation method of artificial wave with complete non-stationarity is proposed.Not only the overall spatial variability and non-stationary amplitude are considered,but also the non-stationary of frequency is also taken into consideration.Non-stationarity of wave amplitude is expressed by the traditional envelope function,and frequency non-stationary is incarnated by phase difference spectrum.Aiming at the power spectral density function of Clough-Penzien model, value of peak ratio of ground motion in simulation is advised.2.Multiple performance objectives are discussed and several advices are proposed. Taking one multi-story frame structure and a high-rise frame-shear wall structure as example, four performance objectives of frequent seismic design as buildings of category C,frequent seismic design as buildings of category B,non-yielding design under moderate earthquake as buildings of category C and elastic design under moderate earthquake as buildings of category C are studied.Engineering quantity analysis and incremental dynamic analysis indicate that the collapse resistant capacity can’t be improved evidently for frame structure designed according to moderate seismic at 6 intensity fortification zone while the capacity enhanced greatly in 7 or 8 intensity zone.However,the quantity are also increased significantly for moderate seismic design in 7 or 8 intensity zone,so it must be cautious in design,or it is impossible to realize.Finally,collapse resistant capacity of frame structure in Wenchuan is also analyzed with the strong ground motions recorded in Wenchuan,in which the building are designed according to seismic fortification 7(pre-earthquake) and 8(post-earthquake) respectively.3.A three level performance objective of seismic capacity evaluation for field-shoring-structure system is proposed and realized in design.It is concluded by the analysis of a real project in Fujian province that only slight subsidence without sliding occurred under frequent earthquake;moderate subsidence and certainly sliding at adjacent river bank generated under moderate earthquake;significant subsidence and sliding will be caused by rare earthquake.The seismic inner force of shoring structure indicate that the scheme of double-row supporting pile can meet the objective of ’no cracks under frequent earthquake,no yielding under moderate earthquake and no collapse under rare earthquake’.4.The seismic performance of field and shoring structure under multi-point excitations at bedrock are analyzed using the generated multi-point artificial waves.It is shown that the ground motion parameters,horizontal relative displacement and vertical subsidence of field, as well as the seismic inner force of supporting piles can usually be diminished.However, some seismic responses are still amplified,such as moment of retaining wall at river bank and horizontal relative displacement at the top of supporting piles.5.The influences of field nonlinearity on seismic performance of super high-rise building under bidirectional horizontal seismic excitation are analyzed.It is indicate that,for high-rise frame-shear wall structure,the absolute acceleration,story drift and seismic inner force of structural member at different stories may be amplified on the consideration of the field nonlinearity,so it may approach to danger when reduced according to Chinese seismic code.Under bidirectional horizontal seismic excitations,the larger reduction factor shall be taken as the influences of field nonlinearity on seismic response at the two directions are different.As a result,single reduction factor specified in Chinese seismic code is irrational.更多还原