两层钢管混凝土组合框架结构抗震性能试验研究

拟动力试验方法最早是由日本学者于1975年提出的,它综合了拟静力试验、振动台试验和时程反应数值分析的特点,来实际模拟结构损伤、刚度变化产生的非线性行为,近年来已得到广泛应用。本文通过对一榀由钢管混凝土柱和组合楼盖经由半刚性连接构成的组合框架1/3比例模型的拟静力、拟动力试验和弹塑性地震反应分析,研究此类结构在地震作用下的动力响应、恢复力特性和耗能性能;其中输入的地震波先采用ElCentro波,后采用Kobe波,模拟结构经历不同的地震作用。实测显示:累积损伤导致结构底层刚度的较大弱化,结构基频下降;钢管混凝土柱屈服,角区混凝土开裂,结构呈现较好的变形延性。本文还根据实测结果建立了一个预测组合框架结构在地震作用下弹塑性性能的分析模型,理论计算和试验结果基本吻合;实验和计算表明钢-混凝土组合框架结构具有良好的抗震性能。     

半刚性连接组合梁框架足尺模型模拟地震振动台试验

为了研究半刚性连接组合梁框架在地震作用下动力特性以及破坏模式,为半刚性框架抗震设计及在地震区的使用提供依据,进行了1个足尺半刚性连接组合梁框架结构模型振动台试验研究。通过试验,分析了小震、中震和大震作用下半刚性连接组合梁框架结构的动力特性、位移反应、加速度反应、半刚性组合节点内力反应、结构破坏模式。研究结果表明:半刚性连接组合梁框架具有较好的抗震性能,在罕遇地震作用下(1.20g),整体结构仍然没有明显损坏,结构破坏形式为半刚性组合节点和柱脚处产生较大塑性变形,半刚性连接框架结构完全可以在高抗震设防烈度地区使用。对试验框架建立有限元分析模型,进行结构的非线性动力时程分析,计算结果与试验结果较为接近。     

扩高比对蜂窝框架抗震性能的影响

研究不同扩高比对蜂窝钢框架抗震性能的影响.以蜂窝式钢框架结构抗震性能试验为基础,利用有限元软件建立合理的有限元模型.对开孔形式相同的蜂窝梁采用不同腹板扩高比框架结构,并模拟低周反复荷载作用下的受力过程和破坏形式.得到了不同扩高比下蜂窝钢框架的滞回曲线、骨架曲线、刚度退化、延性等性能,并进行对比与分析.结果表明:开孔形式...     

Seismic behavior of CFRSTC composite frames considering slab effects

This paper reports on an experimental and numerical investigation conducted on the seismic behavior of concrete-filled rectangular steel tubular columns (CFRSTC) composite frames. The experimental study was conducted by subjecting two full-scale composite frames to simulated seismic loads. Both frames were composed of CFRSTC and steel beams. One specimen was placed on a reinforce concrete (RC) floor slab and the other was not. The purpose of the test was to investigate the elasto-plastic performance of the CFRSTC composite frame system and to examine the effects of composite action on the behavior of composite frames. The test results showed that the stiffness, strength and energy-dissipating capacity of the CFRSTC frame increased significantly with the presence of the floor slab. Compared with a bare steel beam, the composite beam experienced a decrease in the rotation capacity from 0.046 rad to 0.026 rad. The shear deformation of the panel zone grew because of the composite action, which delayed the fracture of the beam. Finite element (FE) models were established to simulate the tested frames. The results of the FE model fit well with that of the test model in terms of stiffness, strength, hysteretic behavior and component deformation.     

8度区异形柱框架结构的振动台试验研究

为深入研究异形柱框架结构的抗震性能,探讨其在高烈度地震区的适用性,以8度区Ⅲ类场地为背景,综合考虑实际工程情况和模型试验的可行性等因素,设计了一个6层的异形柱框架结构为原型。按照加速度相似系数等于1和"用人工质量模拟的弹塑性模型"的要求,采用微粒混凝土制作了1/6比例的试验模型,进行了振动台试验,研究了设计计算方法的适用性、结构的总体抗震性能和破坏机制。根据设计计算的结果、试验中观察到的现象以及对试验结果的分析,在指出该种体系具有易于满足位移要求、在大震中以梁铰机制为主等优点的同时,也指出了其在高烈度区应用的重点问题是节点承载力。     

Hysteretic behaviour of flush end plate joints to concrete-filled steel tubular columns

The results of an experimental research study involving the testing of four bolted moment-resisting connections under simulated seismic loading conditions are presented. Each test specimen modeled the interior joint of a moment-resisting frame consisting of H-shaped steel beams and circular or square concrete-filled steel tube (CFST) columns using high-strength blind bolts. In order to investigate the seismic behaviour of the blind bolted flush end plate joints to CFST columns, the hysteretic performance, failure modes, stiffness degradation and energy dissipation of the connection type are evaluated in detail. The test parameters varied included the column section type and the thickness of the end plate. The experimental results indicate that both the blind bolted connections with circular and square sections exhibited excellent hysteretic behaviour in terms of their moment–rotation response, strain distributions and energy dissipation. Under cyclic loading, all tested specimens displayed large rotation ductility capacities, and the failure modes were similar to those under monotonic loads. The effects of cyclic loading on the behaviour of the composite joint were obvious, especially on load bearing and stiffness of the connections. The joint type exhibited excellent seismic performance, so that it can be effectively utilized in moment-resisting composite frame structures.     

Seismic design, performance, and behavior of composite-moment frames with steel beam-to-concrete filled tube column connections

Concrete filled steel tube (CFT) columns have been widely used in composite-moment frames (C-MFs) both in non-seismic and in high seismic zones. The objective of this research is to develop a design methodology of such moment resisting frame structures designed with CFT columns in achieving ductile behavior and high strength. These composite-moment frames mostly constructed around the perimeter of the building provide the enough stiffness to withstand the lateral displacement due to wind or seismic loads. In this research, three sets of prototype composite frame models were designed on the basis of the proposed design examples as 3-, 9-, and 20-story post-Northridge SAC buildings with composite-special moment frame (C-SMF) systems designed for the western US area. The exact moment-rotational behavior of steel beam-to-CFT column connections including the strength degradation was simulated using the 2D joint model with the rigid boundary element. Nonlinear pushover analyses were conducted on the numerical frame models so as to evaluate the over-strength, inelastic deformation, and P-Delta effect for the entire structure. The statistical investigation was introduced to nonlinear dynamic analyses under 40 SAC ground motions corresponding to a seismic hazard level of 2% probability of exceedence in 50 years in order to efficiently examine seismic performance and behavior of entire composite frame structures. All frame models meet the allowable limit for safe designs. In addition, the entire frame design becomes conservative as the number of stories increases. The distribution of interstory drift ratios (ISDRs) as well as the over-strength ratio also demonstrates this conservative design of low to high-rise CMF structures.     

Cyclic behavior of prefabricated reinforced concrete frame with infill slit shear walls

A composite structural system consisting of prefabricated reinforced concrete frame with infill slit shear walls (PRCFW), with good ductility, is a new type of earthquake resistant structure. Pseudo-static tests were performed to evaluate the seismic behavior of the PRCFW system. Two one-bay, two-story PRCFW specimens were both built at onehalf scale. Additional computational research is also conducted to enhance the nonlinear analytical capabilities for this system. Combined with the concrete damaged plastic (CDP) model provided by finite element program ABAQUS and the constitutive model of concrete proposed by Chinese code, the damage process of the PRCFW structure under cyclic load is simulated. The simulated results show a good agreement with the test data, the dynamic behavior of the PRCFW system can be simulated sufficiently accurate and efficient to provide useful design information. The experimental and numerical study show that this system has the potential to offer good ductility and energy absorption capacity to dissipate input energy, and stiffness adequate for controlling drift for buildings located in earthquake-prone regions.     

冷弯薄壁型钢三层房屋振动台试验研究

为考察低层冷弯薄壁型钢房屋的抗震性能,进行一个三层足尺模型的振动台试验,得到低层冷弯薄壁型钢房屋结构在水平地震作用下的动力特性、地震反应、破坏机理等,并对其抗震性能进行评估。结果表明:结构在振动过程中表现为局部破坏,墙体骨架基本完好;结构呈剪切型变形形式;9度抗震设防时,多遇地震下结构最大弹性层间位移角为1/934,罕遇地震下结构最大弹塑性层间位移角为1/52,满足抗震规范关于抗震变形验算的相关规定;该房屋体系抗侧力的关键在于墙板的蒙皮作用和抗拔件的抗倾覆作用,因此应保证接缝和边角处自攻螺钉的施工质量,抗拔件应采取有效的防松措施。对结构的抗震能力进行初步评估,表明该房屋在9度多遇地震下的墙体剪力均小于其抗剪承载能力,且具有较高的安全储备。     

高位转换消能减震结构振动台试验研究

某超限高层建筑采用钢筋混凝土框架-剪力墙结构,存在高位转换层,其楼板平面开洞尺寸过大,造成楼板平面刚度不连续。弹性分析时,楼层竖向构件最大水平位移与楼层水平位移平均值之比为1.31,属结构扭转不规则,为此结构设计采用了软钢阻尼器来提供附加刚度及阻尼。为研究该高层建筑结构抗震性能,进行了1∶20缩尺模型的振动台试验,获得了模型结构的动力特性及在地震作用下的动力反应,分析了原型结构的地震反应。试验及分析结果表明,该结构满足现行建筑抗震设计规范的抗震设防要求;阻尼器减小了结构的扭转反应,对加速度反应起到了一定的减小作用;转换层上刚度变化较大,应逐步减缓刚度变化,改善相邻楼层的延性;出屋面层的鞭梢效应严重,应重视出屋面层的抗震设计。     

高耸塔台结构地震模拟振动台试验研究及有限元分析

对顶部两层钢框架的高耸筒体塔台结构在地震作用下的动力特性与反应,从模型振动台试验和有限元计算两方面进行了研究。对一个1∶30比例的机场控制塔台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。同时,应用结构有限元分析程序对模型及原型结构进行动力计算,并将两种结果进行比较分析。     

中空夹层钢管混凝土柱与钢-混凝土组合梁节点抗震性能试验研究

以中空夹层钢管混凝土柱与带钢筋混凝土楼板的钢-混凝土组合梁采用高强螺栓及T形钢连接件构成的组合节点的抗震性能为研究对象,对6个十字形组合节点以梁端反对称加载的形式进行拟静力试验。试验中以柱轴压比、加劲肋、T形钢连接件尺寸、楼板厚度和楼板配筋率等为变化参数,研究该组合节点的破坏特征、滞回性能、抗剪性能、承载力衰减、刚度退化规律、耗能特性以及应变变化等力学性能。研究结果表明：柱内置钢管在增加柱受压承载力的同时可以有效增加节点核心区受剪能力,改善了节点整体受力性能;增大楼板配筋率(当1%≤ρ≤ρmax时)和减小柱轴压比(当n≤0.3时)能增强节点总耗能能力,但会降低节点延性且对节点承载力无明显提高作用;T形钢翼缘厚度和设置加劲肋对节点抗震性能影响较大。     

Dynamic characteristics and seismic response of frame–core tube structures,considering soil–structure interactions

In order to study the dynamic characteristics and seismic response of high‐rise buildings with a frame–core tube structure, while considering the effect of soil–structure interactions (SSIs), a series of shaking table tests were conducted on test models with two foundation types: fixed‐base (FB), in which the superstructure was directly affixed to the shaking table, and SSI, consisting of a superstructure, pile foundation, and soil. To increase the applicability of the model to the dynamic characteristics of real‐world tall buildings, the superstructure of test models was built at a scale of 1/50. This simulated a 41‐floor high‐rise building with a frame–core tube structure. The mode shape, natural frequency, damping ratio, acceleration and displacement response, story shear, and dynamic strain were determined in each of the test models under the excitation of simulated minor, moderate, and large earthquakes. The SSI effect on frame–core tubes was analyzed by comparing the results of the two test models. The results show that the dynamic characteristics and seismic response of the two systems were significantly different. Finally, these results were verified by performing a numerical analysis on the differences in the seismic responses of the FB and SSI numerical models under various simulated seismic conditions.     

陶板幕墙模拟地震振动台试验研究

通过钢框架外挂足尺陶板幕墙模型的振动台试验,研究了陶板幕墙的抗震性能。试验分别输入El-Centro地震波、人工波及Taft记录波。试验结果表明,陶板幕墙系统具有良好的抗震性能,符合抗震设计要求。     

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.     

A modified friction damper for diagonal bracing of structures

In this paper, the dynamic behavior of a recently developed friction damper has been demonstrated. It is made from nine steel stripes and nine high strength steel bolts and is applied in the diagonal bracing of structures. This device has a square geometric shape and should be installed in the square spans. During this research work, a prototype of the modified friction damper was tested by a universal machine. Then the damper was installed inside a SDOF steel frame and tested by the shaking table under several earthquake excitations. For numerical assessment of the system, the model of SDOF frame was created in SAP2000 and analyzed under the same excitations which had been applied during the shaking table tests. By comparing the results obtained from SAP2000 to those of experimental tests, the validity of numerical modeling was proved. In order to assess the behavior of damper in multi-story buildings, the model of a four story frame, with and without the modified damper, was created in SAP2000 and analyzed under several seismic records. The results were indicating that the lateral displacements and the base shears of the multi-story building have been significantly reduced by the installation of this modified energy absorber and a considerable energy has been dissipated by the damping system.     

混凝土异形柱-钢梁装配式节点受剪性能试验研究

为研究混凝土异形柱-钢梁装配式框架节点核心区的受剪性能,按照预制混凝土异形柱中预埋钢牛腿节点未加强、增配X形筋、增配X形钢板三种方式,分别制作3个预制混凝土异形柱-钢梁节点试件进行拟静力试验,得到其破坏特征、承载力、滞回曲线、刚度退化、耗能能力等抗震性能指标。由节点剪切变形、节点区钢筋应变、钢板应变测量结果,分析了不同牛腿加设方式对节点核心区受力性能的影响。结果表明：试件位移延性系数在3.22~5.94之间,破坏时位移角都超过1/50,抗震性能良好;牛腿内侧加设的X形钢筋与X形钢板均与节点核心区混凝土协同受力,可有效提高节点核心区受剪承载力。采用有限元软件ABAQUS对采用X形钢板增强的试件进行了数值模拟和参数分析,依据试验分析结果,推导出X形钢板增强的预制异形柱-钢梁混合装配式框架节点核心区受剪承载力计算公式,计算结果与试验实测值和有限元模拟值吻合较好。     

半刚接钢框架-钢板剪力墙结构滞回性能的有限元分析

为研究半刚接钢框架-钢板剪力墙结构(Partially-restrained Steel Frame Steel Plate Shear Wall)的抗震性能,利用经试验验证的双向等效拉杆模型分析了低周往复荷载作用下梁柱半刚性连接对强、弱框架SPSW结构滞回性能、承载力、刚度、耗能能力的影响.分析结果表明:SPSW结构的滞回曲线具有双重特征,当周边钢框架较强时,滞回曲线趋于饱满;当内填剪力墙板较强时,滞回曲线趋于捏缩.随着节点抗弯承载力的增加,强、弱框架的SPSW结构的滞回性能趋于饱满,耗能能力增强,水平承载力呈增大趋势,但对强框架SPSW结构的影响程度大于弱框架SPSW结构.节点抗弯承载力对强框架SPSW结构的抗侧刚度影响较大,对弱框架SPSW结构抗侧刚度影响相对较小.     

大型火电厂钢结构主厂房铰接中心支撑框架体系的振动台试验研究

为获得铰接中心支撑框架结构体系的抗震性能,以位于抗震设防烈度8度区的某大型火电厂钢结构主厂房横向最不利一榀的煤仓间部分为原型,按1∶12缩尺比例设计制作了试验模型,并对其进行了14种地震工况下的模拟地震作用振动台试验。得到了模型结构的动力特性、阻尼比及其在8度多遇、基本和罕遇烈度下的加速度和位移响应等。结果表明:8度多遇地震作用前后结构第1阶频率为4.59Hz,8度罕遇地震作用后,第1阶频率减小为4.40Hz,但梁柱仍然完好,仅有个别支撑和节点板出现了微小的平面外变形。依据试验与有限元分析结果,推算出试验原型结构在三种地震(E l Centro、CholamShandon、人工地震)的多遇烈度以及人工地震的罕遇烈度下,层间位移角均满足我国现行抗震规范要求。该体系在高烈度区也可具有良好的抗震性能。     

钢梁-钢筋混凝土柱组合结构研究的进展

近年来,在组合结构中出现一种新型的结构形式,即由钢筋混凝土柱和钢梁(RCS)组成的框架结构。本文较为系统地阐述国际上RCS组合结构抗震性能的研究情况。主要包括RCS梁柱节点的试验研究、RCS组合框架的试验研究和有限元分析、RCS组合结构的抗震设计及性能分析,以及美日“设计指南”的完善与发展。最后指出RCS结构研究存在的问题和今后的研究趋势。