Dynamic racking tests of curtain wall glass elements with in-plane and out-of-plane motions

This project was conducted to investigate the breakage and fallout behaviour of various types of architectural glass elements in a dry-glazed curtain wall system under in-plane and out-of-plane dynamic motions. The project was a follow-up to an earlier project that focused exclusively on in-plane dynamic racking performance of curtain wall glass elements. The recent data indicated that adding out-of-plane motions caused significantly higher amounts of glass breakage and subsequent glass fallout in most glass types that were found during the in-plane tests to be prone to glass fallout. Specifically, 1/4 in (6 mm) annealed monolithic glass, 1/4 in annealed monolithic glass with a 0·004 in (0·10 mm) PET film (not anchored to the mullions), and 7/16 in (11 mm) fully tempered laminated glass exhibited comparable or higher fallout rates than the already substantial fallout rates that were observed during the in-plane only racking tests. Unanchored window film was found to be ineffective in resisting post-breakage glass fallout under dynamic racking motions. In contrast, 1/4 in (6 mm) annealed laminated glass and 7/16 in (11 mm) heat-strengthened laminated glass exhibited no glass fallout during the out-of-plane tests, just as they exhibited no fallout during the in-plane tests. Out-of-plane test results also showed that 3/8 in (10 mm) heat-strengthened monolithic glass exhibited no fallout, while 3/8 in annealed monolithic glass exhibited very negligible glass fallout. The addition of torsional motions was not found to induce glass fallout in those glass types that resisted glass fallout in previous tests performed without torsional motions.     

配筋砌体结构墙体出平面反应试验研究

为研究配筋砌体结构出平面反应,将配筋砌块未注芯的孔灌注了高密度铁砂,以提高缩尺模型材料的等效密度,更真实地模拟墙体出平面惯性效应.利用推导的模型与原型的相似关系,设计并实施了振动台试验.结果表明,模型结构主要以压弯变形为主,在现行规范规定的构造措施下,足以抵抗设防地震造成的墙体出平面破坏.通过敲击试验得到墙体出平面振动频率,该频率相对较高,远离地震动卓越频率.相邻楼层出平面频率不完全相同,振动的相位可能时而同相,时而反相.     

截面中部配置型钢的混凝土剪力墙抗震性能研究

本文通过试验研究了型钢混凝土(SRC)剪力墙的抗震性能,对16个试件进行了低周反复加载试验,得到了这些构件的延性比;研究了高宽比等参数对型钢混凝土剪力墙抗震性能的影响。在试验中,研究了在中部配置型钢的型钢混凝土剪力墙,结果表明这种新型的型钢混凝土剪力墙具有更好的抗震性能。在试验的基础上,本文建立了型钢混凝土剪力墙恢复力骨架曲线的数学模型,为分析高层结构的非线性地震反应分析提供了基础数据。     

Nonlinear dynamic analysis of reinforced concrete shear wall structures

During strong ground motions, structural members made of reinforced concrete undergo cyclic deformations and experience permanent damage. Members may lose their initial stiffness as well as strength. Recently, Los Alamos National Laboratory has performed experiments on scale models of shear wall structures subjected to recorded earthquake signals. In general, the results indicated that the measured structural stiffnesses decreased with increased levels of excitation in the linear response region. Furthermore, a significant reduction in strength as well as in stiffness is also observed in the inelastic range. Since the in-structure floor response spectra which are used to design and qualify safety equipment have been based on calculated structural stiffness and frequencies, it is possible that certain safety equipment could experience greater seismic loads than were specified for qualification due to stiffness reduction.In this research, a hysteresis model based on the concept of accumulated damage has been developed to account for this stiffness degradation both in the linear and inelastic ranges. Single and three-degrees-of-freedom seismic Category I structures were analysed and compared with equivalent linear stiffness degradation models in terms of maximum displacement responses, permanent displacement, and floor response spectra. The results indicate significant differences in response between the hysteresis model and equivalent linear stiffness degradation model at PGA levels of greater than 0.8 g. The hysteresis model is used in the analysis of reinforced concrete shear-wall structures to obtain the in-structure response spectra. Results of both cumulative and one shot tests are compared.     

改善混凝土剪力墙抗震性能的研究

混凝土剪力墙被广泛运用于各类结构体系中。它作为主要的抗侧力单元,其刚度大、承载力高,但当剪力墙以受剪破坏为主时,其抗震性能较差。为此,不少学者提出了各种改善混凝土剪力墙抗震性能的措施。本文对几种采用不同构造措施的剪力墙作了简要介绍,特别是介绍一种新型双重组合剪力墙。     

Cyclic tensile-compressive tests on thin concrete boundary elements with a single layer of reinforcement prone to out-of-plane instability

The growing need for residential housing in Latin American countries has led to the construction of reinforced concrete buildings with wall thicknesses as low as 8–10 cm. Such walls have typically only a single layer of vertical rebars and are therefore particularly susceptible to out-of-plane failure. In order to investigate the response of the corresponding wall boundary elements, twelve reinforced concrete members with a single layer of vertical rebars were tested under tension–compression cycles. The objective was to gain insight into the parameters governing wall instability and out-of-plane failure, namely the thickness, reinforcement ratio, and eccentricity of the longitudinal rebars with respect to the member axis. This paper summarises the results of the test program, where the specimens' response is analysed also at the global and local levels. The results show that the crack pattern has an important influence on the out-of-plane behaviour and the conditions leading to out-of-plane failure are described. Furthermore, the differences between members with a single layer of vertical rebars and members with two layers are discussed. The influence of the parameters considered in the experimental program is addressed, showing that sections with small thickness and large reinforcement content are more prone to out-of-plane failures. Finally, predictions given by existing models are compared to the new experimental data. The entire data set is publicly available.     

钢纤维混凝土低剪力墙抗震性能试验研究

对不同钢纤维体积率、相同钢纤维混凝土强度的5个钢筋钢纤维混凝土低剪力墙试件以及不同钢纤维混凝土强度、相同钢纤维体积率的2个钢筋钢纤维混凝土低剪力墙试件,进行了低周反复荷载作用下的试验研究,分析了剪力墙的延性、滞回性能和耗能能力等,研究了钢纤维体积率和钢纤维混凝土强度对钢筋钢纤维混凝土低剪力墙的延性及耗能能力的影响.试验和分析结果表明:掺加钢纤维的钢筋混凝土低剪力墙的延性、耗能能力都比普通钢筋混凝土低剪力墙明显提高,抗震性能良好.     

Experimental assessment of low-aspect-ratio,reinforced concrete shear wall stiffness

Low-aspect-ratio, reinforced concrete shear walls are the primary lateral-load-carrying element in many structures designed for protective purposes. A review of the technical literature shows that considerable uncertainty exists regarding the elastic stiffness these structures will exhibit during seismic excitation. Because of this uncertainty, current design practice often employs a stiffness reduction factor. In an attempt to develop accurate information regarding the stiffness of these structures, 13 shear wall elements were tested statically; dynamically, with simulated seismic base excitations on a shake table; and with experimental modal analysis procedures. Results of these tests show that the shear wall's stiffness can be accurately estimated with a mechanics-of-materials analysis that accounts for shear deformation.     

剪力墙结构层间位移计算方法探讨

规范对高层剪力墙结构层间位移进行限制时,没有考虑结构体系侧移模式不同的影响,这对以弯曲变形为主的结构会造成很大的误差,甚至得出一些与实际情况完全不相符的结论。针对这一问题,本文根据剪力墙结构的受力特点,将楼层位移分为有害位移和无害位移,将层间位移分为名义层间位移Δui和有害层间位移Δui~,用倒三角形分布水平荷载的等截面悬臂杆件的弯曲变形曲线作为剪力墙结构的近似侧移曲线,从理论上分析了剪力墙结构的名义层间位移、有害层间位移、层间相对转角以及截面的弯曲曲率之间的关系,给出有害层间位移的实用计算公式。最后,对比分析了控制剪力墙层间变形的几种不同方法,并通过算例分析验证了本文方法实用可行,与实际情况符合较好。     

Substructure hybrid testing of reinforced concrete shear wall structure using a domain overlapping technique

An online hybrid test was carried out on a 40-story 120-m high concrete shear wall structure. The structure was divided into two substructures whereby a physical model of the bottom three stories was tested in the laboratory and the upper 37 stories were simulated numerically using ABAQUS. An overlapping domain method was employed for the bottom three stories to ensure the validity of the boundary conditions of the superstructure. Mixed control was adopted in the test. Displacement control was used to apply the horizontal displacement, while two controlled force actuators were applied to simulate the overturning moment, which is very large and cannot be ignored in the substructure hybrid test of high-rise buildings. A series of tests with earthquake sources of sequentially increasing intensities were carried out. The test results indicate that the proposed hybrid test method is a solution to reproduce the seismic response of high-rise concrete shear wall buildings. The seismic performance of the tested precast high-rise building satisfies the requirements of the Chinese seismic design code.     

Development and modeling of a frictional wall damper and its applications in reinforced concrete frame structures

A wall‐type friction damper is newly proposed in this paper to improve the performance of reinforced concrete (RC) framed structures under earthquake loads. Traditionally, the damper was generally invented as a brace‐type member. However, it has been seen to cause problems in the RC frame structures in that concrete is apt to be damaged in the connection regions of the RC member and the brace‐type damper under earthquake loads. The proposed wall‐type damper has an advantage in the retrofit of RC structures. The system consists of a Teflon® slider and a RC wall. The damper is also designed to control normal pressures acting on a frictional slider. The numerical applications show that the proposed damper can be effective in mitigating the seismic responses of RC frame structures and reducing the damage to RC structural members. Copyright © 2004 John Wiley & Sons, Ltd.     

钢筋混凝土核心筒体抗震性能分析

本文在非线性有限元计算模型和分析程序的基础上，对影响钢筋混凝土核心筒体抗震性能的三个重要参数，即高宽比、轴压比、连梁刚度比，进行了一系列模型的非线性计算分析，得出了各参数对核心筒的承载力、破坏形式、延性、耗能能力等抗震性能的影响，为参数影响的定量研究和工程设计提供了有价值的参考。     

H形断面钢筋混凝土立体剪力墙的非线性动力响应分析

为了建立统一的动力响应分析模型,本文以NUPEC振动台试验的H形断面钢筋混凝土立体剪力墙为研究对象进行了三维非线性有限元动力响应分析。根据分析结果与试验结果的比较可知,在RC剪力墙到达最大承载力之前由简化模型和一般模型得到的动力响应特性与试验结果吻合较好,荷载-变形关系能很好模拟试验结果。但是,最大承载力之后,由于混凝土开裂、损伤、劣化的急剧发展,较难模拟混凝土开裂、裂缝的开闭及滑移等非线性特性,分析得到的加速度衰减较慢、位移响应较小。基于上述研究成果探讨并提出了进一步改善非线性有限元动力响应分析精度的建议。     

Cyclic testing of moment-shear force interaction in reinforced concrete shear wall substructures

Previous quasi-static cyclic tests of shear walls, which routinely used an incremental lateral displacement test protocol with a constant axial load, failed to reflect the character of moment-shear force interaction of prototype buildings. To study the effect of the moment-shear force interaction on the seismic performance of shear walls, three identical 2-story shear wall specimens with different loading patterns were constructed at 1/2 scale, to represent the lower portion of an 11-story high-rise building, and were tested under reversed cyclic loads. The axial force, shear force and bending moment were simultaneously applied to simulate the effects of gravity loads and earthquake excitations on the prototype. The axial force and bending moment delivered from the upper structure were applied to the top of the specimens by two vertical actuators, and the shear force was applied to the specimens by two horizontal actuators. A mixed force-displacement control test program was adopted to ensure that the bending moment and the lateral shear were increased proportionally. The experimental results show that the moment-shear force interaction had a significant effect on the failure pattern, hysteretic characteristics, ductility and energy dissipation of the specimens. It is recommended that moment-shear force interaction should be considered in the loading condition of RC shear wall substructures cyclic tests.     

型钢混凝土低矮剪力墙抗震性能试验研究

剪力墙构件是现代高层建筑结构中的主要抗侧向力构件.为了对比型钢桁架混凝土组合低矮剪力墙与型钢框架混凝土组合低矮剪力墙以及普通钢筋混凝土低矮剪力墙在地震作用下的抗震性能,本文进行了四榀1/4缩尺模型的低矮混凝土剪力墙在单调和低周反复荷载作用下的对比试验,其中单调加载试验包括一榀内置型钢桁架的型钢混凝土组合低矮剪力墙,反复加载试验包括一榀普通钢筋混凝土低矮剪力墙、一榀内置型钢框架的型钢混凝土低矮剪力墙和一榀内置型钢桁架的型钢混凝土低矮剪力墙,给出了各试件的刚度、承载力、变形、延性和破坏形态等试验结果,并对其进行分析.试验结果表明,在这三种墙体中,型钢桁架混凝土组合低矮剪力墙的承载力、变形能力、耗能能力较其他类型剪力墙好,并为型钢桁架混凝土组合低矮剪力墙在实际中的应用提供了试验依据.     

高强钢筋混凝土短肢剪力墙抗震性能试验研究

通过对采用高强钢筋的6片T形混凝土短肢剪力墙和采用高强钢筋高强混凝土的6片L形短肢剪力墙进行低周往复加载试验,研究了T形和L形的破坏形态与性能差异,分析了高厚比、轴压比、配箍间距等参数对构件破坏形态、滞回耗能、骨架曲线、延性及耗能等抗震性能的影响,对比分析了构件与普通短肢剪力墙的抗震性能差异。试验结果表明:采用腹板端部箍筋加密的方式可减轻构件端部的损伤和降低正负向加载时承载力和延性的不对称性;T形构件中高厚比为5的试件表现为弯曲破坏,其他构件表现为弯剪破坏;试验中高厚比小的构件相对于高厚比大的试件延性耗能更好,轴压比增大,构件承载力提高但延性降低;与普通短肢剪力墙相比,T形短肢剪力墙承载力和变形能力提高,耗能增加,L形短肢剪力墙承载力提高较大,极限位移增大,构件后期变形能力略有降低,但可以满足抗震性能要求。     

砖墙-钢筋混凝土墙组合结构震害预测方法

建筑物震害预测对于制定城市防震减灾规划意义重大,对于我国高烈度区建造的砖墙-钢筋混凝土剪力墙组合结构,目前没有成熟的震害预测方法.为了预测西昌市砖墙-钢筋混凝土剪力墙组合结构建筑物在不同地震烈度下可能发生的震害程度,通过分析该种结构在不同地震作用下的受力特点,提出以结构薄弱层的楼层屈服强度系数为指标进行震害预测,并结合...     

钢筋混凝土耗能支撑框架结构的震害预测

首先介绍了一种新的震害预测方法——基于模糊概率的震害预测模型。在分析了钢筋混凝土框架结构抗震性能以及摩擦耗能支撑框架结构在地震作用下力学性能的基础上，提出用结构层间屈服强度系数、层间剪切位移角和地震损伤指数这三个指标作为其主要震害影响评价因子。同时，利用所提出的预测方法，建立了钢筋混凝土耗能支撑框架结构房屋的震害预测模型。