欠人工质量缩尺振动台试验结构模型设计方法

振动台试验是研究结构抗震性能的重要方法。以单跨六层钢筋混凝土框架结构为例,对满足一致相似律的不同配重模型分别按构件等面积配筋率和按构件承载力相似原则进行配筋设计的缩尺模型与原型,采用有限元软件SAP2000和MSC.MARC分别进行了Pushover分析和弹塑性时程分析。分析结果表明：模型钢筋与原型钢筋性能相同（不完全满足相似关系）而模型混凝土性能满足相似关系要求时,按构件等面积配筋率配筋的缩尺模型不能正确反映原型的地震响应,高估原型的抗震能力;按构件承载力相似原则进行配筋设计能够较好地解决这一问题;当构件配筋率较高时,配重不足因素的影响小。针对按构件承载力相似原则配筋设计的方法,提出按模型钢筋弹性模量比修正杆件面积配筋率的改进建议。图8表11参18     

带抗拉装置高层隔震结构振动台试验研究

西昌（9度区）某高层基础隔震结构,其上部为框架-核心筒结构,总高度为58.3m（不计入隔震层）,隔震层采用铅芯橡胶隔震支座。为研究该隔震结构的抗震性能及检验带抗拉装置隔震支座的有效性,进行了缩尺比为1/15模型的模拟地震振动台试验。结果表明,隔震层降低了上部结构的加速度反应,隔震层上加速度放大系数小于0.5,可满足抗震设防烈度降低一度的设计目标;隔震结构的位移集中在隔震层,上部结构的层间位移较小,层间位移角满足规范层间位移角限值要求;隔震层力-位移滞回曲线较为饱满,具有良好的耗能能力。罕遇地震作用下,支座出现拉应力,说明隔震结构在高烈度地震作用下存在倾覆的可能性。对角部隔震支座加装抗拉装置后,再次进行振动台试验,结果表明,抗拉装置不会对结构水平向动力特性及支座在正常受压状态下的竖向运动和水平向运动产生显著影响,通过对比证明了其在隔震支座受拉情况下提供的有效抗拉作用。     

Equivalent multi-phase similitude law for pseudodynamic test on small scale reinforced concrete models

Small scale models have been frequently used to experimentally investigate the seismic performance of structures because capacities of testing facilities are limited and because they are more economically viable. However, not enough studies have been carried out on the development of similitude laws for accurately analogizing prototype structures with small scale models. Furthermore, conventional similitude requirements based on geometry may not be suitable in the inelastic range. When a small scale model of a prototype reinforced concrete structure is fabricated from a similar material to the prototype, an added mass would generally be required due to the volumetric variation, while the scale factor, as a ratio of the scale model to the prototype, cannot be sufficiently reduced due to the limitation of aggregate size. As an alternative, for small scale models it is desirable to use materials that are dissimilar to those of the prototype. Thus, a modified similitude law can be derived that depends on the geometric scale factor, equivalent modulus ratio and peak strain ratio. In this study, compressive strength tests were carried out to analyze the equivalent modulus ratio of micro-concrete to normal-concrete. The equivalent modulus ratios could then be divided into multi phases of strain level, which are basically dependent on the peak strain level at ultimate strength. An algorithm adaptable to the pseudodynamic test was therefore developed that considers an equivalent multi-phase similitude law based entirely on strain levels. Prior to carrying out the physical experiments, a numerical simulation was performed by idealizing the designed specimens to a single degree of freedom system with a bilinear model, and the pseudodynamic testing algorithm was numerically verified from seismic responses. A prototype and a 1/5 scale model of reinforced concrete columns as a test specimen was designed and fabricated based on the equivalent modulus ratios already defined. As a preliminary test, quasi-static tests on test specimens were carried out and their experimental results were compared using the constant and variable modulus ratios. Furthermore, in the pseudodynamic test on small scale models, it was verified that the modified pseudodynamic testing algorithm that considers the developed equivalent multi-phase similitude law may offer better simulation of the prototype structures than the conventional pseudodynamic testing algorithm. Therefore, it is found that the equivalent multi-phase similitude law would be applicable to the pseudodynamic test on small scale models.     

非对称剪力墙-简体超高层结构的振动台试验研究

为了研究复杂体型高层建筑结构在地震作用下的特性与反应，对一个l：50比例的非对称剪力墙一双筒体复式超高层住宅模型进行了振动台模拟地震试验。根据试验结果，通过相似关系得到原型结构在地震作用下的动力特性与反应，与有限元分析结果进行了比较，指出了结构的薄弱部位，并对结构设计提出了若干建议。     

混凝土板在近距离化爆作用下的相似分析

通过对爆炸作用的JWL方程和混凝土的HJC模型量纲分析,得到了混凝土板在化学爆炸作用下响应的相似关系,相似关系表明化学爆炸的爆压与比例距离有关,爆炸冲击波载荷作用下,在相同的缩放比例条件下,结构应力和应变满足几何相似模型律。     

Study on dynamic response of large and small aspect ratio isolated buildings

An experimental study of a large aspect structure, 1:4 scale five‐storey steel frame, is presented. Seismic responses of the test model to the unilateral and bilateral excitations are compared. The effects of aspect ratio on the maximum acceleration, the storey drift of the superstructure, the maximum displacement and the vertical load of the isolation system are investigated. A comparison of the large aspect ratio isolated building with the small aspect ratio isolated building showed significant difference of the effects of aspect ratio subjected to disparate earthquake ground motions. Experimental results reveal that the aspect ratio is an important factor influencing the axial load action on isolators and the tension stress of the lead‐rubber bearings. The superstructure flexibility of the large aspect ratio building‐isolation system and the effects of the axial force variation of the lead‐rubber bearings should be carefully considered for design. Copyright © 2013 John Wiley & Sons, Ltd.     

Shaking table model test and numerical analysis of a long‐span cantilevered structure

This paper presents an earthquake‐resistance study program of a long‐span cantilevered story building. The program consists of a shaking table test study and nonlinear seismic analysis using finite element modeling technique. A 1/30 scale model of the prototype structure was designed and manufactured and then tested via the shaking table facility. Dynamic responses of the prototype structure under different earthquake excitation loadings were simulated. Dynamic properties, acceleration, and deformation responses of the scale down model under different intensity levels of earthquake were studied. The dynamic behavior, cracking pattern, and the likely governing failure mechanism of the structure were analyzed and discussed as well. The seismic responses of the prototype building were deduced and analyzed in terms of the similitude law. Furthermore, elaborate finite element models were established, and nonlinear numerical analysis of the prototype structure was conducted. The errors in the seismic response of the structure caused by structural simplification of scale down modeling are found small, and the dynamic behavior of the structure was not altered in the earthquake excitations. This test study provides a benchmark to calibrate the finite element model and a tentative guide in seismic design of such long‐span cantilevered story buildings.     

建筑结构的地震模拟试验研究

利用小比例尺模型的振动台试验定量估计建筑结构的地震反应和抗震性能,是我国抗震试验研究的新动态。本文就动力相似律在小比例模型试验中的应用作了分析,着重探讨了结构非线弹性反应的模拟问题,其内容包括:模型设计的一致相似律,忽略重力模型和欠人工质量模型在非弹性阶段的试验误差,以及在不同变形条件下考虑材料非线性的相似律确定等问题。     

Study on the seismic performance of a multi‐tower connected structure

Many reinforced concrete or steel reinforced concrete single‐tower buildings have been built in China. The structural performance of such one‐tower structural systems depends on that of the primary components that are structural walls or moment‐resistant frames. For multi‐tower connected structures, problems become more complex. A multi‐tower connected building, with large floor slab openings in plan and long‐span truss in elevation, was thus studied because of its structural complexity and irregularity. First, a 1/25 scaled model structure was tested on the shake table under minor, moderate, and major earthquake levels. Then, the dynamic responses of the model structure were interpreted to those of the prototype structure according to the similitude laws. The experimental results were also compared with the numerical analysis of a three‐dimensional finite element model for the irregular structure. Both experimental and analytical results demonstrate that, despite of the structural complexity, the overall responses of the building meet the requirements of the Chinese design code and the torsion of the structure is not remarkable. It is suggested that the strength and stiffness of the long‐span connecting truss should be improved due to the potentially large vertical acceleration under strong earthquakes. Copyright © 2009 John Wiley & Sons, Ltd.     

七层混凝土小型空心砌块房屋振动台试验研究

按相似理论设计制作了 1/ 6比例七层混凝土小型空心砌块房屋整体模型。通过在三向六自由度振动台上进行的模拟地震振动台试验 ,研究了模型结构的动力特性 ;研究模型结构在 7度多遇烈度、 7度基本烈度、 7度罕遇烈度、 8度罕遇烈度地震动作用下的自振特性加速度、位移、应变反应 ;研究模型结构的开裂烈度、开裂部位、震害发展情况。并根据振动台试验的结果 ,按相似关系推算七层混凝土小型空心砌块房屋原型结构的地震反应。     

Shaking table tests and numerical analysis of an over-track multi-tower building

This article aims to investigate the seismic performance of a four-tower (frame-shear wall) building with a large frame podium at bottom sitting on a metro depot through shaking table test and numerical simulations. Technical problems generally exist in this type of buildings due to irregularity in elevation and plan, tower offset, and structural transfer. These problems bring challenges to engineers when analysing and predicting dynamic responses under earthquakes which is crucial for structural safety. To evaluate the seismic performance of the building, a comprehensive study which includes a shake table test of the scaled model and time history analyses using a finite-element model is conducted. The shake table test model is designed based on the similitude law with a 1:40 scale. The dynamic characteristics, cracking pattern, failure mechanism, as well as maximum acceleration and deformation response are investigated. The corresponding finite-element analysis shows a good agreement with experimental results. It is concluded that this type of building can achieve the predefined performance objectives with well-behaved transfer floors. Shear failure at weak story is considered as a main failure mode of the structure. The whipping effect of stories on the top of structure is remarkable. There is no severe damage in steel reinforced concrete beams. Finally, some design suggestions are also proposed to improve the seismic performance of this type of buildings.     

基础隔震在高烈度区大高宽比剪力墙结构中的应用与试验研究

根据预期减震目标,对总高度90.35m,高宽比达3.96,设防烈度为8度（0.2g）的玉溪公租房项目中基础隔震高层剪力墙结构,按照7度设防对上部结构进行设计,对其进行罕遇地震作用下静力弹塑性（Pushover）分析,并对隔震结构整体进行非线性时程分析。设计并制作了1∶12.5的缩尺模型,对其进行振动台试验研究。结果表明：基础隔震高层剪力墙结构呈现出良好的抗震性能及较高的地震安全储备;在8度多遇、设防地震作用下,结构完好,前5阶频率基本未发生变化,结构尚处于弹性状态;在8度罕遇地震作用下,仅少数连梁轻微开裂;结构层间位移角、隔震支座最大位移、支座应力均未超过规范限值;隔震层滞回曲线饱满、耗能显著;在9度超罕遇地震（0.7g）作用下,未出现倾覆、局部倒塌现象,仅少数连梁、剪力墙出现轻微损伤,频率最大衰减幅度小于10%,刚度下降不明显。     

底框砌体结构转换层隔震系统工作机理研究

层间隔震是在基础隔震发展过程中出现的一种新型减震技术。底框砌体结构在城市建设中应用广泛,这种房屋的特点是由两种承重和抗侧力体系构成的,但是这类房屋的抗震性能较差。通过把隔震橡胶垫放置在上部砌体与底层框架结构之间的隔震措施,依靠隔震层较大的变形和耗能能力,大大削弱了地震对建筑结构的影响。由于上部砌体的刚度比隔震垫与底层框架的刚度大得多,因此可以将隔震房屋模拟成具有两个自由度的系统。分析了此类房屋的动力特性,与隔震振型的参与系数相比,非隔震振型的参与系数是非常小的,隔震振型控制了系统的反应,得到了用来求解此类房屋动力计算的实用方法,探讨了组合阻尼比、刚度比及质量比的变化规律。为建立实用设计方法、推广层间隔震结构的应用提供了有效途径。     

基础隔震结构高宽比限值研究

本文研究目的是得到隔震结构在各种工况下的高宽比限值,这对隔震结构设计是必要的。橡胶隔震支座不能产生拉应力和隔震支座压应力不超过容许值是保证隔震结构在强震中不产生倾覆的充分条件。基于这两个条件,本文推导了隔震结构高宽比限值的显式并给出了针对不同建筑类别、不同设防烈度、不同场地条件和不同隔震层阻尼比的高宽比限值。在支座的轴力计算中,考虑了水平地震作用、竖向地震作用和重力荷载代表值的共同影响以及荷载的最不利组合。研究发现,当控制条件为支座不产生拉应力时,高宽比限值随隔震结构周期的增加而增加;当控制条件为支座压应力不超过容许值时,高宽比限值随隔震结构周期的增加而减小。因此,存在一个临界周期使高宽比限值取得极大值。研究还发现,存在一个最大的隔震结构周期使高宽比限值等于零或隔震层位移超过容许值。将隔震结构的周期与临界周期和最大隔震周期比较,就可以得到相应高宽比限值的表达式。     

多铅芯橡胶支座力学性能研究综述

总结了多铅芯橡胶支座的研究及试验成果,指出多铅芯橡胶支座具有良好的滞回耗能能力和受力性能,并具水平刚度大、稳定性能高、阻尼稳定等优点。概括了多铅芯橡胶支座研究、应用需要解决的内容。     

基础隔震建筑简化软碰撞保护与变刚度保护的对比分析

基础隔震建筑通过设置隔震支座来保护上部结构不受损坏,但在长周期或强烈地面运动作用下会使隔震支座变形过大而导致隔震支座失稳破坏。在这种情况下,需增设保护装置作为第二道防线,以减小隔震层的变形,使之限制在允许的范围内,同时上部结构层间剪力不明显增大。本文主要对比分析了两种保护措施:①简化后的软碰撞保护;②变刚度保护。通过对其原理、力学模型以及工程实例的研究,选取了恰当的参数并进行了地震反应分析。     

底部两层框架砌体结构模型试验及动力相似关系

本文介绍了底部两层框架砌体结构模型试验的振动台试验结果 ,并通过两种不同比例的动力反应参数进行比较 ,讨论了采用小比例模型试验的主要动力参数的相似关系 ,可作为此类结构模型的动力试验参考。     

隔震橡胶支座保护方法

在基础隔震建筑中 ,隔震橡胶支座保护上部结构 ,其自身也应该被保护而不发生失效。本文对隔震橡胶支座提出了三种保护措施 :软碰撞保护、变刚度保护和软着陆保护 ,并对工作原理进行了分析。     

Shaking table test and numerical analysis of a high‐rise building with steel reinforce concrete column and reinforce concrete core tube

This paper assesses the seismic performance of a high‐rise building with steel reinforce concrete column and reinforce concrete core tube in Shanghai, China. This building has 54 floors above the ground and 4 basements, and it has two strengthened layers, which are composed of outrigger truss and belt truss. In order to validate the reliability and the safety of this structure, besides the conventional analysis, shaking table test of scale model was conducted. In the test, the maximum responses of acceleration and deformation were measured and evaluated, as well as the dynamic characteristics, crack pattern, and failure mechanism of the building. Meanwhile, elastic‐plastic time‐history analysis for prototype structure was carried out by the finite element analysis program, and the experimental data were compared with the analytical results to gain a better understanding of the seismic performance of the building. The conclusions are summarized below:

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拱形立体桁架结构振动台试验研究

为研究拱形立体桁架结构在强震作用下的破坏模式,以一实际工程为背景,对拱形立体桁架结构进行缩尺比例为1/15的振动台试验。对模型相似比的选取、模型设计以及加载方案、测点布置等进行说明,得到各级人工波作用下,模型自振频率、阻尼比、加速度反应、位移反应以及杆件应变,研究模型自振特性的变化规律,获得拱形立体桁架结构在强震作用下的破坏模式。研究表明,随地震波峰值加速度的增大,结构各向自振频率和等效刚度降低,结构阻尼比增大。地震波向模型顶部传播过程中,加速度和位移响应随结构高度逐渐放大。当输入峰值加速度达到0.8 g时,结构刚度迅速下降,主桁架斜腹杆大量屈曲;当输入峰值加速度达到1.0 g时,结构刚度下降50%,发生平面内反对称变形。