考虑填充墙影响的钢筋混凝土厂房结构地震易损性分析

采用对角斜撑模拟纵向填充墙的作用,建立考虑填充墙和不考虑填充墙厂房结构模型,采用拉丁超立方抽样技术建立考虑材料不确定性的结构分析样本,基于随机Pushover分析确定结构不同破坏状态下的统计参数。综合考虑结构材料强度及输入地震动不确定性的影响,通过非线性时程分析开展单层钢筋混凝土厂房结构易损性研究,在此基础上比较结构横、纵向易损性的差异,研究填充墙对结构易损性的影响。研究结果表明:钢筋混凝土厂房结构体系横向地震易损性显著大于纵向地震易损性;对纵向结构体系而言,加入填充墙会明显降低结构易损性,但在相同强度的地震动作用下,填充墙破坏程度比主体结构严重,这与厂房结构的实际震害特征相符。     

基于不同破坏指数的建筑物震害预测不确定性分析

结构地震破坏指数是将结构地震破坏程度进行量化的指标,其应用领域十分广泛。本文针对建筑结构震害预测工作,选取了7种典型的破坏指数,分别以5层和17层钢筋混凝土结构为模型,计算了在给定地震动作用下,结构模型对应于每个破坏指数的结构震害等级。计算结果表明:由于选取的破坏指数以及相应的破坏等级划分不同,建筑物的震害预测结果会存在较大的差异,尤其在接近设防烈度的地震作用下,建筑物的震害预测结果存在很大的不确定性。     

形状记忆合金混凝土框架建筑抗震性能研究

地震作用会造成钢筋混凝土框架发生平面和垂直方向的变形,导致其结构受到更大的地震力,加剧损伤程度。形状记忆合金(SMA)材料在外力作用下能够快速恢复变形前形状,降低框架损伤程度,进一步提高框架结构的承载能力和稳定性。基于此,有必要研究形状记忆合金混凝土框架建筑的抗震性能。以某实际工程为例,采用ANSYS软件建立钢筋混凝土框架有限元模型,选取天津地震波、北岭地震波、印度洋地震波及人工地震波作为地震震动输入,记录地震震动下时程结果。研究结果表明,预应力筋断裂后,该结构在地震作用下的滞回曲线为饱满的旗帜形,最大层间位移为1/125,残余变形在±10 mm之间,最高峰值荷载为211 kN,水平承载力较强,表明其自复位性能较高、地震响应效果较优、抗震承载力较强,可以有效提高建筑结构的安全性和可靠性。     

钢结构建筑钢板外部震动下承载力有限元分析

传统钢结构建筑钢板外部震动下承载力分析方法,是基于总体钢板结构以及受力特征,获取载荷同振动频率间的关系,实现承载力的分析,并未对钢板同混凝土间的应力-应变关系进行分析,导致分析结果存在较高的偏差。提出新的钢结构建筑钢板外部震动下承载力有限元分析方法,将钢结构建筑钢板横截面简化成混凝土的矩形截面和波纹钢板的工字形梁截面,采用ANSYS有限元软件中的CONTACI2接触单元仿真分析钢板同混凝土两者的影响,分析混凝土及钢板的应力-应变关系、界面模块的应力-滑移关系,采用力平衡迭代法获取外部震动下钢板荷载增量;在上述基础工作上采用有限元软件,对外部震动下钢结构建筑钢板实施有限元接触单元建模及承载力分析。实验结果表明,该方法能够实现钢结构建筑钢板外部震动下承载力有限元分析,并且分析结果具有准确性高和效率高的优点。     

基于一致可靠度的地震动记录样本容量确定方法研究

确定地震动输入样本容量是开展结构动力地震反应分析的重要环节,目前国内外关于地震动输入样本容量的讨论往往忽略或尚难以定量考虑结构地震反应估计的可靠度水平。以一实际钢筋混凝土框架结构为例,首先分析在大样本地震动作用下结构非线性地震反应的统计特征,研究估计结构地震反应时取样本最大值和平均值的差异,然后借助于假设检验分析结构地震反应的概率分布模型,给出基于一致可靠度的地震动样本容量确定方法,并对比分析单周期点、多周期点、谱值匹配调整地震动及人工合成地震动对样本容量需求的影响,为保证在小样本地震动输入下结构地震反应估计值满足给定可靠度和容许误差提供分析方法和判断依据。本文方法适应于定量确定不同结构类型和不同地震强度水平下的地震动样本容量需求,对建筑结构抗震性能评估及设计规范研究有一定意义。     

多维地震作用下钢筋混凝土建筑结构的抗连续倒塌仿真分析

为了提高钢筋混凝土建筑结构的抗震性能,分析多维地震作用下钢筋混凝土建筑结构的抗连续倒塌能力,结合钢筋混凝土建筑结构特性、节点构造特点以及其在多维地震作用下的破坏机理,采用离散单元法建立结构连续倒塌的理论模型,对建筑结构连续倒塌过程进行数值模拟。基于数值模拟化结果,通过备用荷载路径法,实现建筑结构的抗连续倒塌分析。仿真实验结果得出,所提方法能实现对建筑结构抗连续倒塌的准确分析,且在多维地震作用下建筑结构扭转的幅度明显变大,结构顶层位移发散状态显著,不同楼层会产生不同的层间位移以及薄弱部位,建筑结构的抗连续倒塌性能随着失效构件位置的提升而增强。     

锈蚀钢筋混凝土框架中节点抗剪强度研究

随着服役时间的增长，侵蚀环境下钢筋混凝土框架节点因钢筋发生不同程度的锈蚀而造成承载性能下降，严重影响建筑结构的安全使用。本文在已有钢筋混凝土框架节点抗剪强度理论模型的基础上，考虑钢筋锈蚀对框架节点受力性能的影响，建立锈蚀钢筋混凝土框架中节点受剪承载力计算公式。通过11组锈蚀钢筋混凝土节点试验数据，对建议理论模型进行验证。研究结果表明，锈蚀钢筋混凝土节点受剪承载力试验值与理论计算值之比的平均值为0.951，方差为0.075，二者吻合较好，本文建议的计算方法可用于锈蚀钢筋混凝土框架中节点承载力分析。     

钢框架加劲肋壁板结构的受力失稳性能研究

钢框架壁板由于在宏观上参与了整体建筑结构的受力,为钢框架构件承担部分外荷载,使得壁板结构在受力性能方面需要进一步改善。加劲肋壁板可以保证其与外框架的连接状况较好,改善整体构件的受力性能。为此,提出钢框架加劲肋壁板结构的受力失稳性能研究。采用动力学分析方法计算壁板结构位移值,依照位移值大小判断壁板结构是否处于稳定状态,获取壁板结构稳定性。利用实例测试分析钢框架加劲肋壁板结构的受力失稳性能,发现滞回曲线形状拥有梭形滞回曲线的特点,整个结构受力后具有塑性变形性能与抗震性能;骨架曲线反映出实验试件承载力支持第一阶段壁板结构弹性设计所需且提供第二阶段弹塑性抗震设计所需以及延性要求,本文检测模型能够判断钢结构建筑壁板结构失稳性。     

罕遇地震下多、高层支撑体系塑性极限的计算机分析

根据已建立的框架-斜撑结构的在水平地震作用下的破坏模式和极限承载力表达式，编制了计算程序。通过程序计算，可以得出结构在不同破坏模式下的承载力值。通过对承载力值进行分析，可以确定结构在水平地震作用下的最小荷载和最可能破坏模式。     

基于构件破坏概率的地铁车站震害预测方法研究

<正>本文对地铁车站结构从构件的破坏过程、破坏准则以及破坏等级入手,对给定地震动条件下地铁车站结构震害预测的概率方法进行了研究。首先通过对钢筋混凝土构件的统计分析与数值模拟,基于构件层面并依据试验结果分析了保护层混凝土外缘被压碎及极限破坏状态对应曲率的试验推定值与理论计算值比值的分布情况,依此提出了构件破坏概率的计算方     

钢筋混凝土框架结构震后可存活概率预测方法研究

针对当前钢筋混凝土震后存活预测相关方法存在预测值与实际值拟合度低的问题,提出基于有限元的钢筋混凝土框架结构震后可存活概率预测方法。利用混凝土本构模型关联数值和钢筋本构模型数值计算,实现钢筋混凝土框架材料本构模型关联数值分析。结合建筑和结构施工图实现钢筋混凝土有限元模拟,将钢筋混凝土框架有限元模型的最大竖向荷载作为结构整体构造竖向极限承载力,并引入随机Pushdown方法及随机竖向IDA法得到钢筋混凝土框架震后可存活概率。经实验证明,将有限元应用至钢筋混凝土框架结构震后可存活概率预测中切实可行;预测值与实际值拟合度高于目前常用方法。所提方法的性能完善,可为该领域发展提供可借鉴的信息。     

地震区居民建筑钢结构极限承载力测试与分析

传统方法一般依据静力检测数据测试居民建筑钢结构的极限承载力,对构件数量的要求较高,无法量测隐蔽构件,测试结果精度低。因此提出基于振动参数以及动力模型修正的地震区居民建筑钢结构极限承载力预测与分析方法,分析建筑钢结构振动参数与极限承载能力的关系,塑造地震区居民建筑钢结构简化以及振动方程,获取其极限载荷与振动参数间的关系。采用基于动力模型修正的极限承载力评估方法,基于动力模型修正理论,采用线性屈曲法、几何非线性法以及双重非线性分析法,对地震区居民建筑钢结构极限承载力进行检测。实验结果说明,所提方法能对居民建筑钢结构立柱轴向性和大钩荷载关系以及荷载-扰度曲线,且实施数值运算效果好,预测获取的极限承载力值精度高,建筑的钢结构状态比较稳定。     

高层建筑在连续振动下的壁板结构失稳定BIM模型设计

为了提高高层建筑壁板结构的抗震性,需设计高层建筑在连续振动下的壁板结构失稳定BIM模型。应用软件:通过Revit塑造高层建筑模型和结构模型,结合SAP2000建模性能塑造高层建筑结构的有限元实体模型,实现高层建筑模型的转换,设计BIM模型的IFOD软件总体结构,实现BIM模型的智能化管理。参数:在BIM模型的基础上,分析了连续振动下高层建筑壁板结构风致响应,给出高层建筑壁板结构的平均风响应、脉动风响应,得出高层建筑壁板结构位移,实现了高层建筑在连续振动下的壁板结构稳定性分析。实验:实验结果说明,所设计BIM模型可对连续振动下的高层建筑加速度时程以及位移时程进行准确分析,且相比传统方法,本文方法对高层建筑在连续振动下的壁板结构是否失稳判断结果比较准确。     

Evaluation of blast effects on reinforced concrete buildings considering Operational Modal Analysis results

Seismic protection of buildings under risk can be achieved by increasing the knowledge about the behaviour of existing structures. Operational Modal Analysis is a powerful tool used for this purpose all over the world. It provides the dynamic characteristics of structures under operational conditions or some particular environmental issues such as blasts and earthquakes. The main objective of this study is to evaluate blast effects on a reinforced concrete (RC) building considering experimentally determined dynamic characteristics. The study consists of three phases: the measurement of vibration characteristics of blasting, the theoretical modal analysis of the inspected building, and experimental verification of dynamic characteristics using modal testing. The vibration characteristics of blasting are measured around the inspected building on hard soil using a geophone set. The initial analytical model of the building is constructed according to the in-situ investigation on building. The theoretical modal analysis results are verified by carrying out modal testing on the RC building. The Operational Modal Analysis method is used for the extraction of the dynamic characteristics of the building, and blast vibrations are taken into account as environmental vibrations. The effects of blasting on the reinforced concrete building are introduced by assessing the vibration of blasting with the dynamic characteristics of the building.     

Cladding influence on dynamics response of tall buildings

Precast concrete panels form attractive facades for steel frame buildings and are generally regarded as non-structural by structural engineers. However, panels have been found to add lateral stiffness until their capacity or that of their connections is exceeded. Consequently, the computed dynamic response based on a model of the structural framing alone may be quite different from that experienced by the actual structure. As a case study, the influence of precast concrete panels on lateral and torsional stiffness of a 25-storey building was investigated. The effect of cladding on dynamic properties and linear seismic response was explored by varying panel stiffness. Cladding stiffness was added to the bare frame model until analytical frequency values matched vibration test results. Then, using the cladding stiffness values obtained, an accidental eccentricity between centres of mass and rigidity at each floor level was imposed and linear seismic response computed. Torsional response effects were increased substantially. Finally, a modified cladding panel connection was developed based on previously-reported studies for panelized construction. The influence of the proposed connection on overall structural response was determined for different ground motion inputs.     

Description and analysis of building damage due to Pyrgos, Greece earthquake

On March 1993 an earthquake of magnitude M_s = 5·5 shook Pyrgos, a town in Western Peloponnissos, one of the most seismic prone areas in Greece. The damage induced to modern reinforced concrete buildings was rather light in contrast to the damage induced to historic and traditional buildings of adobe, stone or brick masonry which was severe. In order to study the causes of structural damage, detailed data are collected from a rather large statistical sample of 1023 masonry buildings and 22 reinforced concrete framed buildings with visible damage. For each building the number of storeys, the material of construction, as well as the type and the degree of damage are recorded. In addition, consideration is given to the site of the building within the town and the corresponding soil conditions. For reinforced concrete buildings, damage occured mostly in areas with relatively high estimated spectral accelerations and fundamental soil periods of vibration close to those of the buildings. Nevertheless, further analysis is required to explain the selective damage of a very small number of buildings. For masonry houses, the effect of soil conditions is more systematic. Moreover, the effects of the number of storeys as well as the age and material of construction appear to be dominant.     

Pseudo-dynamic tests on masonry residential buildings seismically retrofitted by precast steel reinforced concrete walls

A retrofitting technology using precast steel reinforced concrete (PSRC) panels is developed to improve the seismic performance of old masonry buildings. The PSRC panels are built up as an external PSRC wall system surrounding the existing masonry building. The PSRC walls are well connected to the existing masonry building, which provides enough confinement to effectively improve the ductility, strength, and stiffenss of old masonry structures. The PSRC panels are prefabricated in a factory, significantly reducing the situ work and associated construction time. To demonstrate the feasibility and mechanical effectivenss of the proposed retrofitting system, a full-scale five-story specimen was constructed. The retrofitting process was completed within five weeks with very limited indoor operation. The specimen was then tested in the lateral direction, which could potentially suffer sigifnicant damage in a large earthquake. The technical feasibility, construction workability, and seismic performance were thoroughly demonstrated by a full-scale specimen construction and pseudo-dynamic tests.