基础隔震结构对随机激励的响应分析

利用过滤白噪声地震动模型，对基础隔震结构进行了随机反应分析。建立了基础隔震结构的运动方程，推导了基础隔震结构位移、加速度对地面随机激励的传递函数表达式，计算了隔震结构与非隔震结构的均方根反应比值。讨论了基础隔震结构主要参数对结构反应的影响。     

底部两层框架基础隔震建筑非线性动力分析

实际震害表明,建筑物主要受水平地震作用影响。本文基于有限元理论,采用大型有限元分析软件SAP2000 Non linear建立了底部两层框架上部砌体非隔震结构和基础隔震结构的实体模型,并采用非线性时程分析法对此模型进行了两个水平向地震作用的分析。结果表明,底部两层框架上部砌体结构采用基础隔震技术后,结构的水平地震反应明显低于相应非隔震结构。尤其是刚度突变的转换层,隔震后水平地震反应降低很多。     

上部结构与基础隔震层偏心对结构地震响应的影响

随着基础隔震技术的发展,我国在高烈度地区广泛开展基础隔震技术的工程应用必将成为一种趋势,但由于建筑功能和建筑造型的丰富多彩,结构的质量中心和刚度中心也趋于分布不均匀,以三层的钢框架结构为分析模型,利用结构分析软件Sap2000对上部结构质量中心和隔震层质量中心、刚度中心分布不均匀的三种方案进行单向水平地震作用下的非线性时程分析,分析结果表明:上部结构质量中心与隔震层质量中心存在偏心距对结构的扭转效应以及地震响应有较大的影响,减小上部结构的偏心距对调整结构的水平地震响应的影响成效最为显著;对于隔震层而言,隔震层的刚度中心偏心距较质量中心偏心距对上部结构的影响更大,有效控制隔震层刚度中心的偏心距在隔震设计中会更加有效。     

多层基础隔震房屋结构在水平地震力作用下的振动传递

文章将周期结构原理与导纳方法结合起来，分析了带复合结构单元的有阻尼的有限周期系统的波传播和振动特性，得到了有限周期结构自振频率的一般表达式。     

基础隔震结构在侧向碰撞下的地震反应分析

本文针对基础隔震结构和临近构造物发生的碰撞问题进行了计算机三维模拟分析。定义了碰撞影响指标Q,建立了隔震结构的碰撞分析模型,通过弹塑性时程分析,分别从碰撞刚度、上部结构刚度、隔震支座、临近构造物与基础隔震结构的距离、地震动强度等5个方面研究了碰撞对基础隔震结构的影响作用。     

基础隔震结构的非线性动力分析

新的建筑抗震设计规范将隔震结构列入其中，探讨分析了结构基础隔震应用中应注意的问题，提出了非线性动力时程分析计算模型并编制了程序。借助该程序，分析了基础隔震结构在地震作用下的层间位移、加速度和剪力等地震反应并与未隔震相同结构建筑的地震反应进行了对比。     

隔震层竖向刚度对高层基础隔震结构的影响

高层隔震建筑的隔震层在罕遇地震作用下会产生拉应力。本文通过对一栋20层的高层隔震结构,分别采用等拉压刚度模型和不等拉压刚度模型进行动力非线性时程分析,研究叠层橡胶隔震支座竖向刚度模型对高层基础隔震结构动力响应的影响。研究表明,超出线弹性工作范围后,竖向等拉压刚度模型将会低估隔震层的竖向位移量,低估上部结构的动力响应。     

基础隔震结构简化模型的振动参数识别

针对目前隔震工程设计中模型简化方面存在的不足，以隔震体系上部结构层间剪力和隔震层位移这两个主要指标等效为目标函数，用多目标优化算法建立了等代体系刚度及质量的参数识别数字模型。并针对工程设计需要，导出了等代参数的简代计算表达式。工程实例计算表明，用本文简化模型分析得到的上述两个指标结果与原结构的响应时程曲线基本吻合，时域响应峰值的相对误差小于3%。     

Morlet 小波用于环境激励下的模态参数识别研究

本文分别从卷积和Parseval定理的角度推导了非正交小波变换系数的实用计算方法。在环境激励下以互相关函数代替系统的自由响应数据,给出了基于Morlet小波变换的频率、阻尼比的参数识别方法,重点介绍了基于最小二乘法的振型识别技术。采用2层楼仿真算例和潮白河桥应用实例验证本算法,识别结果表明基于Morlet小波变换的模态参数识别技术能够有效地识别出环境激励下系统的模态参数。     

Study on the effect of the infill walls on the seismic performance of a reinforced concrete frame

Motivated by the seismic damage observed to reinforced concrete (RC) frame structures during the Wenchuan earthquake, the effect of infill walls on the seismic performance of a RC frame is studied in this paper. Infill walls, especially those made of masonry, offer some amount of stiffness and strength. Therefore, the effect of infill walls should be considered during the design of RC frames. In this study, an analysis of the recorded ground motion in the Wenchuan earthquake is performed. Then, a numerical model is developed to simulate the infill walls. Finally, nonlinear dynamic analysis is carried out on a RC frame with and without infill walls, respectively, by using CANNY software. Through a comparative analysis, the following conclusions can be drawn. The failure mode of the frame with infill walls is in accordance with the seismic damage failure pattern, which is strong beam and weak column mode. This indicates that the infill walls change the failure pattern of the frame, and it is necessary to consider them in the seismic design of the RC frame. The numerical model presented in this paper can effectively simulate the effect of infill walls on the RC frame.     

Shake‐table tests of a three‐story reinforced concrete frame with masonry infill walls

This paper presents the shake‐table tests of a 2/3‐scale, three‐story, two‐bay, reinforced concrete frame infilled with unreinforced masonry walls. The specimen is representative of the construction practice in California in the 1920s. The reinforced concrete frame had nonductile reinforcement details and it was infilled with solid masonry walls in one bay and infill walls with window openings in the other bay. The structure was subjected to a sequence of dynamic tests including white‐noise base excitations and 14 scaled historical earthquake ground motion records of increasing intensity. The performance of the structure was satisfactory considering the seismic loads it was subjected to. The paper summarizes the design of the specimen and the major findings from the shake‐table tests, including the dynamic response, the load resistance, the evolution of damage, and the final failure mechanism. Copyright © 2011 John Wiley & Sons, Ltd.     

工作状态下梁及桥梁模态与损伤识别的新方法

工作状态下桥梁结构的模态参数识别是桥梁损伤识别的重要环节,考虑桥梁检测的实用性,桥梁检测一般应建立在环境激励的基础上,已有的环境激励下模态参数识别的方法对模态频率的识别的精度较高,而对位移模态的识别则误差较大。提出了一种利用移动质量块在不同位置时对桥梁的模态频率进行多次测量,用各次测得的频率值确定位移模态的新方法,使得位移模态识别的精度接近频率识别的精度,建立了该方法的初步模型,推导了频率与位移模态关系的理论公式,并通过数值模拟对该方法的有效性进行了说明。     

Influence of masonry infill panels on the vibration and stiffness characteristics of R/C frame buildings

Vibration measurements were performed on two adjacent, three-storey reinforced concrete frame buildings with hollow clay brick infill panels. The first building was a bare frame and the second one was a similar frame infilled with brick panels. The fundamental period for the infilled frame building was much smaller than that of the bare frame building. Using shear beam lumped mass models and the vibration data the actual lateral stiffness of both buildings was identified. The lateral stiffness of the infilled frame building was found to be seven times that of the bare frame building. Four numerical models of the infilled frame building were constructed. The frame and floors were represented using an experimentally validated model and the infill panels by one of three commonly used ‘equivalent diagonal truss’ models or by plane stress finite elements. Only the plane stress finite element model produced a reasonable agreement with the experimental results. Copyright © 1999 John Wiley & Sons, Ltd.     

大跨度预应力混凝土连续刚构桥的动力特性分析

介绍了福建泉州后渚大桥——大跨度预应力混凝土连续刚构桥的现场环境振动实验．并利用频域中的单模态识别法(SDOFI)、峰值法(PP)和时域中的随机子空间识别法(SSI)分别进行桥梁动力特性识别。利用ANSYS建立了全桥三维有限元模型并进行了理论模态分析,基于参数分析和环境振动测试结果对有限元模型进行了标定,建立了该桥的基准有限元模型,该模型可服务于桥梁长期健康监测与状态评估。     

Effects of infill walls and floor diaphragms on the dynamic characteristics of a narrow‐rectangle building

Most buildings in Singapore are lightly reinforced concrete structures, which are mainly designed for gravity loading only, because Singapore is an island country located in a low‐to‐moderate seismic region. The dynamic properties of a typical high‐rise residential building with a long, narrow rectangular floor plan are studied using both experimental and numerical methods. The effects of the brick infill walls and the flexible diaphragms on the dynamic characteristics of the building are discussed in detail. The results from the ambient vibration tests are correlated with the numerical results of three different finite element models with different levels of sophistication. They include a bare frame model, a frame model with brick infill walls, and a frame model with both brick infill walls and flexible diaphragms. The dynamic properties of the third model match very well with the measured results in terms of both the natural frequencies and the mode shapes. The correlation results demonstrate the respective effects of the brick infill walls and the flexible diaphragms on the dynamic characteristics of the narrow‐rectangle building structure. Copyright © 2006 John Wiley & Sons, Ltd.     

System identification of linear MDOF structures under ambient excitation

This paper introduces the eigenspace structural identification technique for tall buildings subjected to ambient excitations that are stationary and where only the response time histories are measured. Based on the forward innovation model of the Kalman filter sequence, the actual response can be constructed as a function of the measured response time history with contamination of either displacement or velocity. The response time history is decomposed into subspace matrices using QR decomposition and Quotient Singular Value Decomposition (QSVD) techniques. These are then substituted into the least-square formulation to obtain the solution which is non-unique. Similarity transformation is applied to arrive at the desired solution employing the fact that eigenvalues of self-similar systems are identical. The advantages of this eigenspace technique are that it is non-iterative, initial estimates of the parameters to the identified are not required, well-established numerical algorithm of the decomposition techniques employed are available, and the method can handle MDOF systems efficiently. Copyright © 1999 John Wiley & Sons, Ltd.     

基于环境激励的ERA方法在网架结构振动测试中的应用研究

基于环境激励的结构振动测试的方法中ERA方法是重要的时域分析方法.本文主要是以随机减量法(RD)和NExT两种数据处理方法结合ERA算法,对绥化学院正在建的网架结构的基本模态参数进行测试.通过分析比较得出RD/ERA和NExT/ERA较直接ERA有更高的精度,且实测分析结果与有限元分析结果较吻合.为网架结构在环境激励下用ERA方法测试模态参数提供了实验依据.     

环境激励下基于波动能量法的结构损伤识别

目前作为结构健康监测系统核心的损伤识别大多是基于模态参数变化而进行的,但模态参数对局部损坏不敏感,导致损伤识别精度不够。波在结构中的传播状态可以更好地反映局部损伤状况,波动能量可以作为损伤识别的有效指标。为了提高环境激励下结构损伤识别的精度,采用S变换分析了结构输出信号,建立波动能量指标,从而使波动能量指标的使用领域扩展到非平稳信号范围。最后通过三层钢框架试验及弹性分层剪切梁的数值模型对该方法进行了验证,结果表明:该方法不仅能够有效识别结构损伤位置,而且能够识别出损伤程度。