内藏钢桁架混凝土组合高剪力墙抗震性能试验研究

进行了3个1/3缩尺的高剪力墙的抗震性能试验研究,包括1个普通混凝土高剪力墙、1个内藏钢框架混凝土组合高剪力墙和1个内藏钢桁架混凝土组合高剪力墙。在试验研究基础上,对比分析了各剪力墙的刚度及其衰减过程、承载力、延性、滞回特性及破坏特征。试验表明:内藏钢框架混凝土组合高剪力墙的抗震性能比普通混凝土高剪力墙明显提高;内藏钢桁架混凝土组合高剪力墙的抗震性能比普通混凝土高剪力墙显著提高。     

SRC-RC竖向混合结构过渡层抗震设计方法探讨

首先介绍了SRC-RC竖向混合结构的受力特点和性能优势;并针对我国和日本的相关规程及工程应用实践,结合日本阪神地震中SRC-RC竖向混合结构的主要震害特点,指出国内外SRC-RC竖向混合结构过渡层抗震设计方法所存在的主要问题及不足。在综合分析阪神地震后日本关于SRC-RC竖向混合结构过渡层抗震设计方法的最新研究进展的基础上,提出了SRC-RC竖向混合结构过渡层抗震设计的设计思路和方法,可为SRC-RC竖向混合结构过渡层抗震设计提供参考。     

基于性能的框架结构抗震设计研究

对国内外基于性能的抗震设计研究成果进行了较系统的综述与分析,研究表明,基于性能的抗震设计能够对结构在未来可能地震作用下的性能进行有效的控制,使破坏和损失限定在可接受的范围内。在此基础上,本文还初步提出了钢筋混凝土框架结构基于延性的抗震设计建议。     

Uncoupled rocking and shear base-mechanisms for resilient reinforced concrete high-rise buildings

High-rise buildings are an efficient solution to meet the housing challenges of global urbanization that is happening at an incredible pace. Code-based seismic design philosophies are aimed at achieving collapse-prevention under major earthquakes, implying extensive structural damage associated with important losses. A number of high-performance systems have been investigated for enhancing the resilience of high-rise buildings whose design is especially challenging due to higher-mode effects even when a flexural mechanism is formed at the base of the structure. To this end, this paper proposes a new concept consisting of a three-dimensional uncoupled rocking and shear mechanism system for high-rise buildings where reinforced concrete (RC) core walls are used as the lateral-force-resisting system. The proposed system provides a dual-mechanism at the base that independently limits both overturning moments (OTMs) and shear forces and thus more effectively mitigates higher-mode effects. The characteristic mechanics of the proposed system are first studied through an idealized model. A physical embodiment is then designed, detailed, and validated through advanced models and extensive nonlinear dynamic analyses. A 42-story RC core-wall building that is located in Los Angeles and was studied as part of the PEER Tall Buildings Initiative is used as a reference structure in this study. Results confirmed that the proposed system eliminates damage at the base of the walls and minimizes the inelastic demands over the height of the building. In a general sense, the proposed concept provides a framework in which the intended dual mechanism can be implemented to a wider range of high-rise structures.     

钢筋混凝土框架结构层间位移角与构件变形关系研究

层间位移角已作为检验建筑结构抗震性能的主要指标之一而被广泛应用。为实现该指标在钢筋混凝土框架结构基于位移的抗震设计中的应用,研究了层间位移角与构件变形之间的关系。首先,采用对部分子结构的弹性理论分析得到了弹性阶段梁变形对层间位移角贡献比例的计算公式。接着,采用对15层钢筋混凝土框架整体结构的非线性地震反应计算结果的统计分析得到了在塑性阶段梁变形对层间位移角的贡献比例回归计算公式。所建立的计算公式反映了梁与柱的相对刚度和强度比例、层闽塑性变形程度的影响。最后,应用该方法进行了一算例分析,计算结果和试验结果比较一致。利用本文提出的计算方法可以方便地把对框架结构的层间位移需求转变为对梁、柱构件的变形要求。     

关于钢结构抗震存在的问题及建议

本文探讨了目前钢结构抗震设计中存在的两个主要问题:其一是钢结构的地震作用,由于多高层钢结构房屋被列入“建筑抗震设计规范”(GB50011-2001)中时没有考虑钢结构延性好和弹性阶段阻尼比较小的特点,使得钢结构地震作用偏大,用钢量偏高;其二是钢结构承载力抗震调整系数对梁和焊缝的规定与焊缝强度高于母材强度的实际情况不符,造成设计困难。本文对现行抗震规范、“建筑工程抗震性态设计通则”和美国UBC规范的地震作用进行了分析比较,提出按照耗能能力将钢结构体系分为四类,在此基础上引入结构体系调整系数,对每类结构的地震作用取值给出建议。针对梁柱刚性连接,从抗震设计原则出发,对7、8和9度区分别建议了适合采用的连接形式,并给出了小震和大震下的设计验算公式。     

高层隔震结构扭转分析

为研究高层隔震结构在地震作用下的扭转效应,用Etabs软件建立1个高层抗震结构和4个具有不同扭转特性的高层隔震结构的空间模型进行地震响应分析,以验证此原则上部结构质量中心与隔震层刚度中心的重合与否对结构扭转效应的影响程度,而后考察偏心高层隔震结构在偶然偏心地震作用下结构的扭转效应。结果表明:由于地震作用的减小,扭转效应要远小于原抗震结构,且隔震本身对于结构扭转效应的抑制效果要好于上述原则;扭转效应的减震率大于平动效应的减震率。布置在隔震层平面外围的铅芯橡胶隔震支座对隔震层的扭转有一定的控制作用。     

不同轴压比下内藏钢桁架混凝土组合剪力墙抗震研究

轴压比是影响剪力墙抗震性能的一个主要因素,直接决定其延性性能。本文对两组共六个高剪力墙1/3缩尺的试件模型进行了不同轴压比下的低周反复荷载试验,研究了轴压比对内藏钢桁架混凝土组合剪力墙抗震性能的影响,对比了各试件的承载力、刚度及其退化过程、延性、滞回特性及破坏特征。试验表明:随着轴压比的提高其试件的承载力提高但延性下降;不同轴压比下内藏钢桁架混凝土组合剪力墙均能明显提高钢筋混凝土剪力墙的抗震性能。     

多塔高层结构隔震设计与分析

结合某多塔高层隔震结构,采用弹性时程分析方法,分析了隔震结构在多遇地震和罕遇地震作用下的响应。主要包括自振周期、层间剪力、倾覆力矩和楼层位移等内容。结果表明,与非隔震情形相比,结构的自振周期明显增大,地震作用得到了较大的衰减。结构在地震作用下的隔震效果明显,楼层剪力及倾覆力矩均得到折减,在罕遇地震作用下隔震效果尤为显著。层间位移主要集中在隔震层,上部结构的层间位移几乎为零。     

Evaluation of fundamental period of low‐rise and mid‐rise reinforced concrete buildings

Fundamental period of vibration appears to be one of the most critical parameter for the seismic design of buildings because this period strongly affects the magnitude of seismic forces. In this paper, an empirical formula for estimating the fundamental period of reinforced concrete structures is recommended, on the basis of the vibration analysis of 20 different real building configurations. These structures have already been constructed in Greece, and they are analyzed by using in detail 3‐D finite element models and modal eigenvalue analysis. These models take into account the presence of external and internal infill walls, which are usually ignored as nonstructural elements. This neglect leads to unreliable evaluation of period because the infill walls' contribution to the lateral stiffness and therefore to the fundamental period of vibration is also ignored. Furthermore, taking into account that the flexibility of soil elongates the fundamental period, the soil–structure interaction effect is also considered. To achieve a unique, simple, and effective empirical expression for the fundamental period of vibration, a comprehensive nonlinear regression analysis is applied for the datasets of buildings under consideration. This empirical expression is also compared with the similar expressions from the pertinent literature. Copyright © 2013 John Wiley & Sons, Ltd.