结构地震动力可视化分析的快速实现

针对结构时程分析方法的特点，Matlab的数值计算功能和OpenGL的图形功能，实现了空间杆模型结构的地震动力的可视化分析，为快速实现结构地震动力分析探索了一条新的途径，并对利用OpenGL中的动画实时显示技术进行了讨论。     

塑性铰模型对混凝土框架结构动力弹塑性分析的影响

建筑结构在遭遇罕遇大震时,部分结构构件将进入塑性状态.对结构进行弹塑性分析可以更好地掌握建筑结构在大震下的动力响应特性.基于SAP2000软件,分别采用该软件提供的默认塑性铰单元和弹塑性计算用的塑性连接单元,建立混凝土框架结构的弹塑性动力计算模型,输入折线时程曲线和地震记录曲线,进行弹塑性动力时程分析.结果表明,采用刚塑性滞回模型的默认塑性铰单元计算得到的结构加速度响应比采用弹塑性滞回环模型的要低,在使用程序默认塑性铰单元作动力弹塑性时程分析时需要注意考虑该现象对结果的影响.     

维护板对轻钢框架结构体系抗震性能影响分析

通过建立带维护板的6层轻钢框架结构模型,对其进行了模态分析和地震响应弹塑性时程分析,计算得到动力时程分析结果中结构的顶点位移、最大层间位移等数据,并以此分析了维护板对轻钢框架结构体系抗震性能的影响.     

结构地震动力分析可视化初探

本文针对振型分解反应谱法，实现了结构地震动力分析的可视化，为结构地震动力分析探索了一条新的途径，并对动画的制作，控制和动画的实时显示等技术进行了讨论，提出了用于复杂结构的可视化的非均匀弹性体振动动画模型。     

大连国际会议中心结构分析

大连国际会议中心是多筒体大跨悬挑复杂空间组合结构,计算模型杆件数量庞大。在模型建立与分析过程中,为了更好地分析结构的受力形式及状态,采用先分块建模,然后合并模型进行结构设计。根据荷载规范,对结构相应部位施加荷载并进行荷载组合,建立荷载模型。采用反应谱方法和动力时程方法对结构主要指标进行计算分析对比。计算结果表明,在小震作用下,可以采用反应谱方法结果进行设计,在中震、大震作用时,采用反应谱和动力时程方法结果进行性能化指标验算。对整体结构和重点部位抗震性能进行了分析,并提出了相应的结构设计要求。     

建筑结构动力时程响应分析与计算的新方法

基于状态空间理论分析与计算结构动力时程响应问题,根据结构动力学方程,引入结构系统的状态变量,建立结构动力时程响应分析的状态方程,并给出非齐次状态方程的解。对于求解矩阵指数函数有多种解法,着重介绍了凯莱哈密尔顿法、状态空间迭代法和精细积分法。对结构动力时程响应问题按三种解法分别建立了计算格式,并编制了相应计算程序。给出若干数值算例,其计算结果表明,状态空间法分析计算结构动力时程响应精度好、效率高,是一种非常有效的方法。     

风和列车荷载同时作用下车桥系统的动力可靠性

本文提出一种风荷载作用下列车-桥梁体系动力可靠性分析的随机过程峰值分析法.在建立的系统分析模型的基础上,按Davenport风速功率谱模拟产生风速时程的随机样本,应用Monte Carlo模拟技术在计算机上模拟列车过桥的全过程,得到结构动力响应的样本序列.进一步对响应的峰值进行统计,得到其和风速的联合极值概率分布并给出了对其进行可靠性分析的方法.以一座刚梁柔拱组合系桥为例,计算了该桥的使用可靠性指标,并讨论了可靠度计算所必需的结构动力响应的界限值.     

带地下室高层结构在地震作用下的时程分析

建立了带地下室高层结构在多支座干扰条件下的动力计算模型,编制了相应的时程分析程序,对地下室底板和顶板同时输入地震激励,考察了结构的动力反应并与惯常采用的单支座干扰时程分析结果进行了比较。     

基于ETM的钢筋混凝土框架结构抗震分析

ETM是通过对结构输入一条随着时间增加,地震动强度不断增大的地震动加速度时程曲线,进而分析结构从弹性响应到倒塌状态的整个过程。本文基于ETM合成了三条符合我国抗震规范反应谱的耐震时程加速度曲线,并对其反应谱进行了误差分析。使用SAP2000建立一个六层钢筋混凝土框架结构弹塑性模型,并对模型塑性铰设置的可靠性进行验证,最后对结构进行耐震时程分析和增量动力分析,对比分析两种方法得到的最大顶点位移、最大层间位移角、最大基底剪力等结构响应结果。结果表明,合成的耐震时程加速度曲线合理可靠,模型符合分析要求,耐震时程法能较好的预测结构的地震响应,其分析结果与增量动力分析基本吻合,且计算效率高。     

不同支撑对高层建筑结构振动控制分析

为了研究不同形式支撑对高层建筑结构的振动控制的影响,文章通过有限元软件SAP2000建立了一个20层的高层框架结构模型,并以此为基础对结构分别布置中心支撑和偏心支撑,对其进行了模态分析和地震响应弹塑性时程分析.通过计算得到基底剪力最大值和动力时程分析结果中结构的顶部位移最大值、加速度最大值等数据,并以此来分析不同支撑对高层建筑结构振动控制效果.     

Dynamic analysis of a cable-stayed deck steel arch bridge

A theoretical and experimental research work in relation to the cable-stayed Barqueta bridge is described in this paper. Barqueta bridge, across Guadalquivir river, links the city of Seville with Scientific Park Cartuja 93. During rush hour cars may cover one half of the bridge lanes for more than one hour. Full-scale tests were carried out to measure the bridge dynamic response. The experimental program included the dynamic study for two different live load conditions: the bridge with one half of its lanes full of cars, and the bridge empty of cars. Modal parameter estimations were made based on the acquired data. Ten vibration modes were identified in the frequency range of 0-6 Hz by different techniques, two of these modes being very close to each other. The traffic-structure interaction is also studied. Experimental results were compared with those obtained from a three-dimensional finite element model developed in this work. Both sets of results show very good agreement. Finally, a damage identification technique has been applied to determine the integrity of the structure. Results obtained from a test developed in July 2005 have been correlated with experimental results obtained in October 2006 using the damage index method.     

城市高架桥动力特性研究

桥梁结构的动力特性就是结构振动的基本特性,是对桥梁结构进行地震反应分析的基础.因此,对高烈度地区城市高架桥动力特性进行试验和理论研究很有必要.本文以高架桥常见的结构形式桥面连续简支梁结构为例,建立三维有限元模型,进行了模态分析并与试验结果进行对比分析.其结论可为同类型桥梁结构进行设计和分析作为参考.     

银川阅海大桥的主桥设计

银川阅海大桥是宁夏自治区内最大跨径的三肋五孔中承式钢管混凝土系杆拱桥,本文详细介绍了：主桥的结构构造特点;采用空间有限元方法,对该桥进行的静力分析,并对主拱圈的屈曲稳定性进行了分析。同时,给出了结构的动力特征值,并采用反应谱法进行了地震动力响应分析。     

Static strain energy and dynamic amplification factor on multiple degree of freedom systems

Many references and design codes propose the use of a dynamic amplification factor applied to the static response of a structure for estimating its dynamic response. This is the case of the present recommendations on cable stayed bridges or other references for evaluating the dynamic effects produced by the accidental loss of a segment during the cantilever construction of a precast concrete bridge. This paper deals with the dynamic amplification factor of multiple degree of freedom systems under the action of a rectangular pulse load of infinite duration. A theoretical study of the possible maximum values that the dynamic amplification factor can reach has been carried out, establishing the relation between this factor and the strain energy of the system under the load statically applied. This relation allows us to determine if the dynamic amplification factor can exceed the value of 2.0 and to derive a simple method for comparing the dynamic effects of different pulse loads. Finally, a numerical example illustrates this method applied to determine which rectangular pulse load, produced by the accidental loss of a segment of a bridge, can produce a larger and a smaller dynamic amplification factor on a cantilever precast segmental bridge under construction. In this example, the possible maximum dynamic amplification factor obtained has been 3.24.     

Vibration of railway bridges under a moving train by using bridge-track-vehicle element

During the last two decades, much attention has been paid to various vibration problems associated with railways. They include the dynamic response of railway bridges and railway tracks at grade under the action of moving trains. However, studies on the role of track structures on the vibration of railway bridges are rather limited. In this paper, a new element called bridge-track-vehicle element is proposed for investigating the interactions among a moving train, and its supporting railway track structure and bridge structure. The moving train is modelled as a series of two-degree-of-freedom mass-spring-damper systems at the axle locations. A bridge-track-vehicle element consists of vehicles modelled as mass-spring-damper systems, an upper beam element to model the rails and a lower beam element to model the bridge deck. The two beam elements are interconnected by a series of springs and dampers to model the rail bed. The investigation shows that the effect of track structure on the dynamic response of bridge structure is insignificant. However, the effect of the bridge structure on the dynamic response of the track structure is considerable.     

Dynamic test and finite element model updating of bridge structures based on ambient vibration

The dynamic characteristics of bridge structures are the basis of structural dynamic response and seismic analysis, and are also an important target of health condition monitoring. In this paper, a three-dimensional finite-element model is first established for a highway bridge over a railroad on No.312 National Highway. Based on design drawings, the dynamic characteristics of the bridge are studied using finite element analysis and ambient vibration measurements. Thus, a set of data is selected based on sensitivity analysis and optimization theory; the finite element model of the bridge is updated. The numerical and experimental results show that the updated method is more simple and effective, the updated finite element model can reflect the dynamic characteristics of the bridge better, and it can be used to predict the dynamic response under complex external forces. It is also helpful for further damage identification and health condition monitoring.     

Estimation of gross weight,suspension stiffness and damping of a loaded truck from bridge measurements

Particle filter method (PFM) based on Bayesian inference gives a reliable estimate of hidden parameters from the noisy measured signal. A new method of vehicle parameter identification based on measured bridge response has been proposed using PFM. An uncoupled iterative technique is utilised for solving bridge vehicle interaction problem which has been used as a forward solution of the PFM. A field test under moving truck has been conducted on an existing pre-stressed concrete bridge to collect response data at different locations. Based on the extracted bridge natural frequencies and measured peak acceleration responses at five sensor locations, finite element model of the tested bridge has been updated using response surface-based model updating technique. In addition to estimation of test truck parameters using measured bridge response, dynamic wheel load induced in the bridge has been determined. Excellent agreement has been found between the measured and reconstructed bridge response using estimated parameters.     

考虑橡胶支座随机性下隔震与非隔震近海桥梁地震易损性对比

针对目前在隔震桥梁地震易损性分析中隔震支座性能参数随机性研究薄弱、从失效概率的角度开展隔震与非隔震桥梁对比研究缺乏的现状,详细统计分析了橡胶隔震支座力学性能参数的不确定性,建立了近海隔震与非隔震桥梁非线性动力分析模型。在考虑支座参数、地震动及桥梁结构不确定性的基础上,利用拉丁超立方抽样分别生成90个结构-地震动样本对。利用Sap2000有限元软件对每个样本对进行非线性动力时程分析,通过对大量数据的回归分析,得到桥墩、支座的易损性曲线,进而对隔震前后结构的地震易损性进行了对比分析。结果表明：在同一破坏等级相同地震作用下,非隔震桥墩的失效概率大于隔震桥墩,非隔震支座破坏的概率大于隔震橡胶支座|采用隔震技术后,桥墩发生严重破坏和倒塌的概率极低,震后可修复的概率很大|而非隔震桥墩发生严重破坏的概率最大,说明其震后可修复的概率很小而产生不可修复损伤的可能性极大。     

实际车辆荷载作用下的预应力混凝土连续梁桥动力响应分析及验证

以一座三跨单箱单室预应力混凝土连续箱梁桥为对象,利用车辆-桥梁耦合振动关系建立单梁车辆、桥梁运动微分方程,通过二者变形协调、相互作用力协调关系实现车辆-桥梁的耦合关系;修正了自编的桥梁动力响应计算程序,通过建立在桥梁上的高速弯板称重系统实现对实际过桥交通荷载的识别,并将识别出的实际车辆荷载信息输入已建立的桥梁动力响应计算程序,快速计算出在实际车辆荷载作用下的桥梁动力响应,并利用ANSYS软件进行静力验证,用实际过桥车流产生的动应变进行动力验证。     

大跨度三塔斜拉桥地震响应分析

结合某大跨三塔斜拉桥工程设计实例,采用有限元分析程序ANSYS建立动力计算模型。用子空间迭代法对桥梁的动力特性进行了计算,根据桥址场地地震动参数,用反应谱法和时程分析法进行地震反应对比分析。建议在大跨度斜拉桥抗震设计中,以反应谱分析结果作为抗震设计依据,以时程分析结果作为复核。