基于土-结构体系对建筑结构响应的减震效果评估          下载免费PDF全文

徐瑞御  任宏伟 《地震工程学报》2020,42(3):613-623

提出一种基于土-结构体系地震记录的土-结构相互作用(SSI)的减震评估方法。该方法采用简化的SSI模型,通过系统辨识确定模型参数。将上部建筑结构地震反应的SSI减震效应分解为惯性相互作用和运动相互作用,同时还提出由惯性相互作用和运动相互作用单独降低结构响应的方法。将2011年东北地震太平洋沿岸期间两栋中层建筑用此方法进行分析,结果表明:当建筑物结构响应进入非弹性范围时,惯性相互作用的减震效果降低。  相似文献   

利用Munk公式和海底反射走时反演深海水体速度:理论     

孙建国 《吉林大学学报(地球科学版)》2021,51(1):1-12

为解决深海水体速度建模问题，建立了两个利用Munk公式和海底反射走时反演深海水体速度的反演理论，一个是射线走时反演理论，另一个是波动方程走时反演理论。具体地讲，是建立了地震波走时关于Munk参数的Fréchet导数和海森矩阵公式。为得到射线走时的Fréchet导数和海森矩阵，利用了3种不同的方法，即变分法、微扰法和Taylor级数展开法。这3种方法在理论上完全等价，其最终结果也完全相同。为得到波动方程走时反演理论中的Fréchet导数和海森矩阵，利用复合函数求导的链式法则对文献中的有关结果进行变换，以将其从面向速度本身的Fréchet导数和海森矩阵变换为面向Munk参数的Fréchet导数和海森矩阵。此外，还提出了实现利用Munk公式和海底反射走时构建深海水体声速剖面的5个策略，包括利用解析公式计算海底反射走时的由下至上的射线追踪策略，选用最简单的海底边界条件把数值模拟区域限定为水体的策略，用已知的深海声道轴深度和交替反演策略将四参数反演问题转简化为单参数反演问题的策略，由点到面，利用一维声速剖面公式实现深海水体的维速度建模的策略，以及用最简单的算法实现走时反演的最优化计算策略等。与常规走时反演相比，利用Munk公式进行的海底反射走时反演最多只需要反演4个参数，并可利用交替反演将四参数反演化为单参数反演，大大地减少了走时反演的计算量。  相似文献   

大型建筑物三维激光扫描的流程及精度分析     

郭向前  陈富强  郝伟涛 《北京测绘》2021,35(2):208-211

三维激光扫描技术能够提供扫描物体表面的三维点云数据,瞬时测得空间三维坐标值和相应的影像数据,根据获取的空间点云数据快速构建三维可视化模型,精度优良且输出格式多样,能满足不同应用的需求。以扫描大型建筑物为例,论述了三维激光扫描系统的主要构成和工作流程,误差产生的来源及相应的质量控制进行分析,获得满足技术设计要求的扫描数据,为信息数字化发展提供了必要的生存条件。  相似文献   

Ambient vibration studies for system identification of tall buildings     

J. M. W. Brownjohn 《地震工程与结构动力学》2003,32(1):71-95

The performance of a building under wind and seismic loads depends on stiffness and mass distribution, and may be estimated using finite element codes. Experience has, however, shown that such finite element models often fail to predict accurately the fundamental natural frequencies. Usually the frequencies will be underestimated, that is the building will turn out to be stiffer than anticipated, meaning the design would usually be conservative. On the other hand, effects like torsional eccentricity and foundation compliance may not be correctly modelled, which could be less desirable. A full understanding of linear performance under lateral loads can be obtained through experimental evaluation of the vibration modes. Traditionally only a limited range of modal analysis procedures and software has been applied to civil applications and the ‘special case’ where no input forces can be measured has been the usual situation for large civil structures. Recent developments in system identification, which is the set of procedures to build mathematical models of the dynamic structural systems based on measured data, have added significantly to the potential of ambient vibration or ‘output only’ testing. The aim of the research reported here has been to apply and evaluate the procedures on typical buildings. The procedures are briefly explained and two experimental programmes are then described; a long‐term tremor monitoring exercise on a 280m office tower and an ambient vibration survey of a smaller office block. The different forms of response data are examined to study the performance of the analysis procedures and expose benefits and limitations in their use. There is a growing interest in output‐only modal analysis procedures in civil engineering. The experience reported in this paper has shown that quick and reliable estimation of mode shapes and frequencies can be obtained, even with small amounts of data. Judgement of modal participation and damping ratios requires more detailed study yet the results are at least as convincing as existing and relatively limited frequency domain methods. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Optimal maintenance strategies for structures in seismic zones     

R. Montes‐Iturrizaga  E. Heredia‐Zavoni  L. Esteva 《地震工程与结构动力学》2003,32(2):245-264

In this paper an approach is developed for establishing optimal maintenance (repair) strategies of structures in seismic zones. The approach is based on expected future costs and the main decision variable is a damage threshold for repair given an acceptable reliability level. It is considered that structural damage accumulates over a number of earthquakes until a threshold is reached or exceeded, after which the structure is repaired so that there is no remaining damage. A Markov model is implemented for such a process of damage accumulation during future earthquakes. An algorithm is proposed for computing non‐linear structural response to earthquakes using a damage function model. This algorithm is used to evaluate transition probabilities between damage states based on simulations of future earthquakes of given intensities. Expressions are derived for evaluating expected life‐cycle damage costs and structural reliability as a function of time and of the damage threshold for repair. As an application, a single‐degree‐of‐freedom structural system is studied. In addition, the paper addresses the case of instrumented structures where information from earthquake response records is available. Such information is incorporated into the formulation for maintenance strategies by means of a Bayesian approach for updating the probability distribution of structural damage and of non‐linear behaviour parameters so that predictions about costs and reliability are improved. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Studies on seismic reduction of story‐incresed buildings with friction layer and energy‐dissipated devices     

Hong‐Nan Li  Yong‐Wei Yin  Su‐Yan Wang 《地震工程与结构动力学》2003,32(14):2143-2160

A new type of energy‐dissipated structural system for existing buildings with story‐increased frames is presented and investigated in this paper. In this system the sliding‐friction layer between the lowest increased floor of the outer frame structure and the roof of the original building is applied, and energy‐dissipated dampers are used for the connections between the columns of the outer frame and each floor of the original building. A shaking table test is performed on the model of the system and the simplified structural model of this system is given. The theory of the non‐classical damping approach is introduced to the calculation analyses and compared with test results. The results show that friction and energy‐dissipated devices are very effective in reducing the seismic response and dissipating the input energy of the model structure. Finally, the design scheme and dynamic time‐history analyses of an existing engineering project are investigated to illustrate the application and advantages of the given method. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

U-PVC贴砾滤水管井中二次成井技术     

肖西卫  汪晓峰  刘冬生  王旭东 《水文地质工程地质》2003,30(2):77-79

介绍了U-PVC塑料贴砾滤水管井中二次成井的几种方法;以大庆地区的试验为例,说明该技术的优越性。  相似文献   

上海近代建筑的房屋质量检测方法探讨   总被引：1，自引：0，他引：1  

廖文新  朱万明  施玉麒 《上海国土资源》2003,(4):56-58,61

文章介绍了房屋质量检测的主要方法及内容，并结合实例，着重阐述了在近代建筑质量检测中应用的新方法。  相似文献   

琅玡山抽水蓄能电站厂房位置及轴线方向的优化选择   总被引：1，自引：1，他引：1  

李锦飞 《工程地质学报》2003,11(4):416-420

地下厂房位置及轴线方向的选择是一项重要的地质工作,本文在分析琅山抽水蓄能电站厂房区工程地质条件的基础上,就厂房位置及其轴线方向的优化选择,进行了分析和研究。  相似文献   

粉煤灰—CaO胶凝尾矿免烧建筑材料的显微形貌特征及反应机理研究   总被引：2，自引：0，他引：2  

李建平倪文  陈德平汪坤 《地质论评》2003,49(2):201-204

本文利用粉煤灰－CaO无熟料粉煤灰水泥作为生产尾矿免烧建筑制品的胶凝材料，采用常压湿热养护技术，实验研究了粉煤灰－CaO胶凝体系和粉煤灰－CaO－尾矿蒸养体系，运用SEM研究手段，对不同工艺条件下粉煤灰水泥及尾矿建筑材料的显微形貌特征进行了研究，并对蒸养过程中的反应机理进行了探讨。  相似文献