钢-混凝土高层结构抗震性能振动台试验研究

广州天誉大厦采用型钢混凝土框架一钢筋混凝土筒体的混合结构体系,地面以上结构采用抗震缝兼伸缩缝分隔为南、北塔两个独立结构体系,南塔高186.5 m,北塔高159.5 m.两塔的核心筒总宽度与核心筒总高的比值均超出了规范限值.为研究这种超限高层混合结构的抗震性能,对其进行了缩尺(1/30)模型的振动台试验,并建立了有限元计...     

外型钢砼框架—内置型钢框架钢筋砼核心筒混合结构抗震性能试验研究与分析

(超)高层建筑结构一定程度上可代表城市、地区的经济发展水平,其结构体系的选择、承重构件的类型及其连接对其使用功能至关重要。随着我国经济的快速发展,可以预测在今后相当长一段时间内,中国将是(超)高层建筑发展的主要阵地。由于高度超限,抗侧力体系多种多样,其适用范围及适用高度均有所不同,目前还很难形成系统完整的、有针对性的规范、标准等作为设计依据。更需注意的是,一些抗震设防区域或高烈度区也出现了(超)高层建筑结构,且此高度范围的建筑基本均未受到相当强度的地震洗礼。因此,为确保此类建筑结构在地震区的安全可靠,为此类结构抗震设计提供普遍意义上的设计依据,对其抗震性能的研究尤为重要。目前国内外对(超)高层建筑结构,特别是地标性建筑的抗震设计主要根据静、动力试验完成分析,辅以数值模拟完成整体结构的分析作为结构设计的主要依据。本文将采用上述手段对可适用于(超)高层建筑的混合结构体系主要进行如下研究:(1)提出一种新的(超)高层建筑体系,即:外型钢混凝土框架—内置型钢框架的钢筋混凝土核心筒混合结构体系。根据相似原理设计出1:10的模型结构,并进行了地震模拟振动台试验研究;(2)结合振动台试验结果,对该体系中出现的薄弱楼层处的内置型钢框架的组合核心筒体进行了1:2模型的拟静力试验研究;(3)初步探讨了该组合核心筒体的非线性力学性能。论文具体开展并完成了以下工作:(1)提出"外型钢混凝土框架—内置型钢框架钢筋混凝土核心筒"混合结构,探讨其用于(超)高层建筑作为结构抗侧体系的可行性。根据现行规范、规程设计了"外型钢混凝土框架—内置型钢框架钢筋混凝土核心筒混合结构",利用ETABS软件进行了该类结构体系的原型结构整体分析及截面设计。(2)根据相似原理,依据原型结构的基本设计信息,完成了1:10大比例整体模型结构的设计,获得了模型中主要构件的截面设计信息。(3)对该类混合结构模型进行了地震模拟振动台试验,系统分析了整体模型结构在不同类型、不同强度水平的地震动作用下楼层的动力响应,研究了不同工况下模型结构的破坏机理、外框架与核心内筒之间的协同工作性能及整体模型结构的薄弱层位置等,并根据相似关系讨论了对应的原型结构的动力响应及其抗震性能。(4)在振动台试验研究基础上,对内置钢框架钢筋混凝土核心筒体进行了1:2模型结构的拟静力试验。深入研究了该类组合筒体的刚度及承载力变化、耗能机制、滞回特性、变形特点及破坏机理等。进一步分析了内置型钢框架对钢筋混凝土核心筒的承载能力及延性的影响;讨论了内置型钢框架与混凝土间的相互作用及协同工作性能。(5)采用大型建筑结构有限元分析程序STRAT对该内置型钢框架核心筒进行了大震非线性分析及抗震性能研究。上述研究的目的是研究本文所提出的混合结构体系整体抗震性能及其主要抗侧部分—内置型钢框架核心筒体的抗侧能力,探讨该类混合结构在(超)高层建筑结构,特别是地震区高层建筑结构中应用的可行性。本文的研究旨在抗震试验分析的基础上,对该类混合结构体系的综合抗震性能进行全面的分析讨论,对该类结构在地震区的应用提供分析基础,为该类结构体系相应的技术标准、规程的编制与制定提供参考依据,为我国(超)高层建筑结构的发展提供技术保证。     

9度区某超高层结构抗震与减震设计研究

乌兹别克斯坦某银行大厦,结构高度147.1 m, 9度抗震设防,采用钢筋混凝土框架-核心筒体系和组合减震技术。详细论述了该工程的体系选择、抗震和减震设计中面临的技术挑战,以及采取的应对措施。研究表明,9度区超高层结构采用钢筋混凝土框架-核心筒体系时,纯抗震体系无法满足水平位移限值以及构件承载力控制要求,为此采取了组合减震技术,即悬臂桁架黏滞阻尼器减震与金属连梁阻尼器减震措施,分别解决不同地震水平下的整体结构和构件设计问题,通过计算明确了减震措施所能达到的效果。另外,对9度区超高层减震效率和减震产品吨位等关键问题进行了讨论。通过制定合理的性能指标,并对抗震和减震措施进行充分优化和论证,最终保证了结构在不同阶段的性能满足设计要求。     

SRC-RC转换柱的抗震性能分析

首先介绍了我国现行相关规程对SRC-RC竖向混合结构过渡层的设计要求和相关规定,结合阪神地震中SRC-RC竖向混合结构的破坏情况对现行规程的一些规定提出了不同的看法,建议采用SRC-RC转换柱进行型钢混凝土柱到钢筋混凝土柱的过渡。对SRC-RC转换柱低周反复加载试验进行了介绍,分析了型钢锚固长度对SRC-RC转换柱抗震性能的影响。最后对采用SRC-RC竖向混合结构的梁式转换层模型与钢筋混凝土梁式转换层模型进行了对比分析。试验结果表明,对于利用SRC-RC转换柱将型钢混凝土应用到钢筋混凝土结构底部楼层的SRC-RC竖向混合结构,型钢混凝土有效地加强了底部楼层,改善了结构的抗震性能。     

型钢混凝土组合结构在不同抗震区抗震性能初步研究及其结构位移特征的初步探讨

对型钢混凝土梁柱框架结构、型钢混凝土柱-钢筋混凝土梁框架结构、纯钢筋混凝土框架结构进行分析,讨论三者在在不同的地震作用下的层间位移角、有害层间位移角、变形特征曲线上的区别。研究表明:型钢混凝土框架结构呈现剪切型的变形特征,薄弱层出现在首层及二层,大震最大层间位移角可取小震时对应数值的6.5倍进行估算,型钢混凝土框架结构更适用于8度半以上抗震设防烈度地区。     

核心筒抗震性能水准及变形限值研究

为研究核心筒抗震性能水准及其指标限值,完成了3个核心筒拟静力试验,记录了损伤过程及对应的层间位移角。在现有核心筒研究成果及国内外规范的基础上,将核心筒的抗震性能水准划分为4个等级,并给出了相应的宏观描述。通过总结相关试验研究结果,发现《建筑抗震设计规范》(GB50011-2010)对层间位移角限制过于严格,考虑到结构带裂缝工作,层间位移角限制过严会增加建筑成本,并导致结构自重增加而不利于抗震,故建议适当放宽核心筒的层间位移角限值,分别给出框架-核心筒及筒中筒结构最大层间位移角建议值。     

某型钢混凝土框架核心筒消能减震结构的弹塑性分析

某工程位于昆明市,主体结构高153.1m,为型钢混凝土框架-剪力墙核心筒体系。建筑总高度超过了《高层建筑混凝土结构技术规程》中规定的B级高度,为提高结构的抗震性能,该工程采用消能减震技术控制结构的地震反应,对消能减震结构进行了设计,确定了消能器附加给结构的阻尼比值。为给结构设计提供可靠的参考依据,采用PERFORM-3D软件,对设有非线性粘滞阻尼器的该结构进行罕遇地震作用下动力弹塑性时程分析,评估该结构的整体性能及其构件的屈服情况,结果表明该消能减震结构基本能达到预期抗震性能目标。     

直角梯形截面型钢混凝土巨型柱抗震性能试验

某超高层建筑巨型框架采用了直角梯形截面型钢混凝土巨型柱,为研究这种不对称截面型钢混凝土巨型柱的抗震性能及混凝土强度对抗震性能的影响,进行了2个较大尺度的不同混凝土强度的直角梯形截面型钢混凝土巨型柱模型的低周反复荷载试验.比较了2个试件的水平承载力、滞回性能、骨架曲线、刚度、耗能及变形,分析了正、负两向加载下试件抗震性能...     

型钢混凝土边框柱复合墙体抗震性能试验研究

型钢混凝土边框柱复合墙体具有承载力高、抗震性能好的特点,适用于中高层结构。为研究这种结构形式的抗震性能,本文设计了高宽比为1:1、模型比例为1/2及高宽比分别为2:1与3:1、模型比例为1/3型钢混凝土边框柱密肋复合墙体试件,并进行拟静力试验。根据试验结果,分析了型钢混凝土边框柱密肋复合墙体的受力特点、破坏形态、承载能力、延性、耗能以及变形等抗震性能。分析结果表明:型钢混凝土边框柱的破坏过程与普通密肋复合墙体相似;相同条件下,其承载力、延性及耗能能力都明显好于普通复合墙体;边框柱中加入型钢后,该结构体系的抗震性能得到明显提高;随着高宽比的增加,该结构的承载力减小,但延性、耗能增加,型钢的有利作用更加明显。     

高层钢框架-混凝土核心筒混合结构振动台试验研究

为了研究高层钢框架-混凝土核心筒混合结构的整体抗震性能,本文设计了一个典型的比例为1/15的20层钢框架-混凝土核心筒混合结构的缩尺模型,在同济大学土木工程防灾国家重点实验室实施了模拟地震振动台试验。本文重点介绍试验中模型结构在各级水准地震作用下的动力特性、加速度和位移反应,描述了模型结构的破坏位置及过程,并根据相似理论得到了原型结构的地震反应。试验研究表明:原型结构基本能够满足我国现行规范"小震不坏、大震不倒"的抗震设防标准;核心筒发挥了主要抗侧力作用;结构在大震作用下有较好的延性;钢框架与核心筒的连接节点在结构设计时应给予重视。     

Shaking table model test on Shanghai World Financial Center Tower

The height of 101‐storey Shanghai World Financial Center Tower is 492m above ground making it possible the tallest building in the world when completed. Three parallel structural systems including mega‐frame structure, reinforced concrete and braced steel services core and outrigger trusses, are combined to resist vertical and lateral loads. The building could be classified as a vertically irregular structure due to a number of stiffened and transfer stories in the building. Complexities related to structural system layout are mainly exhibited in the design of services core, mega‐diagonals and outrigger trusses. According to Chinese Code, the height 190 m of the building clearly exceeds the stipulated maximum height of for a composite frame/reinforced concrete core building. The aspect ratio of height to width also exceeds the stipulated limit of 7 for seismic design intensity 7. A 1/50 scaled model is made and tested on shaking table under a series of one and two‐dimensional base excitations with gradually increasing acceleration amplitudes. This paper presents the dynamic characteristics, the seismic responses and the failure mechanism of the structure. The test results demonstrate that the structural system is a good solution to withstand earthquakes. The inter‐storey drift and the overall behaviour meet the requirements of Chinese Design Code. Furthermore, weak positions under seldom‐occurred earthquakes of seismic design intensity 8 are found based on the visible damages on the testing model, and some corresponding suggestions are proposed for the engineering design of the structure under extremely strong earthquake. Copyright © 2006 John Wiley & Sons, Ltd.     

消能支撑框架结构的非线性分析

本文介绍了六榀钢筋混凝土支撑框架模型（两榀为普通支撑框架，另四榀为消能支撑框架）在低周反复荷载作用下的工作性能和试验结果；编制了非线性程序，对试验模型进行了计算分析，计算结果和试验实测值符合较好；另外还计算了两榀足尺消能支撑框架结构，研究不同的消能器滑移荷载对结构抗震能力的影响，结果表明消能支撑框架结构具有良好、稳定的抗震性能。     

强震环境下带钢避难建筑抗震模型设计

避难建筑通常采用置换混凝土方法抗震,建筑对高强度地震的抗震性能差。因此提出高强度地震下带钢避难建筑抗震设计方法,采用复杂网络带钢避难建筑加固模型对加固前建筑的混泥土强度与荷载能力进行计算,增大框架柱截面,提升带钢避难建筑荷载。采用复合墙体受力加固模型提升建筑墙体抗震性。对加固后建筑模型的坍塌风险评估时,采用带钢避难建筑坍塌的全概率衡量加固后建筑在设计使用年限内的抗坍塌安全性。设计使用年限内加固后的带钢避难建筑的强震CRC超出概率是P(IMCRC),确保其在高强度地震下具有较高的抗震性能。实验结果说明,所提方法下的带钢避难建筑在遇到强震情况时具有较高的抗震性能。     

Experimental study on the seismic response of braced reinforced concrete frame with irregular columns

A 15-storey K-braced reinforced concrete model frame with irregular columns, i.e., T-shaped, L-shaped, as well as +-shaped columns, was constructed and tested on the six-degree-of-freedom shaking table at the State Key Laboratory for Disaster Reduction in Civil Engineering in Tongji, China. Two types of earthquake records, El-Centro wave (south-north direction) and Shanghai artificial wave (SHAW) with various peak accelerations and principal-secondary sequences, were input and experimentally studied. Based on the shaking table tests and theoretical analysis, several observations can be made. The failure sequence of the model structure is brace→beam→column→joints, so that the design philosophy for several lines of defense has been achieved. Earthquake waves with different spectrums not only influence the magnitude and distribution of the earthquake force and the storey shear force, but also obviously affect the magnitude of the displacement response. The aftershock seismic response of previously damaged reinforced concrete braced frames with irregular columns possesses the equivalent elastic performance characteristic. Generally speaking, from the aspects of failure features and drift ratio, this type of reinforced concrete structure provides adequate earthquake resistance and can be promoted for use in China.     

Cursory seismic drift assessment for buildings in moderate seismicity regions

This paper outlines a methodology to assess the seismic drift of reinforced concrete buildings with limited structural and geotechnical information. Based on the latest and the most advanced research on predicting potential near-field and far field earthquakes affecting Hong Kong, the engineering response spectra for both rock and soil sites are derived. A new step-by-step procedure for displacement-based seismic hazard assessment of building structures is proposed to determine the maximum inter-storey drift demand for reinforced concrete buildings. The primary information required for this assessment is only the depth of the soft soil above bedrock and the height of the building. This procedure is further extended to assess the maximum chord rotation angle demand for the coupling beam of coupled shear wall or frame wall structures, which may be very critical when subjected to earthquake forces. An example is provided to illustrate calibration of the assessment procedure by using actual engineering structural models.     

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。     

Shake table test and numerical study of self‐centering steel frame with SMA braces

Given their excellent self‐centering and energy‐dissipating capabilities, superelastic shape memory alloys (SMAs) become an emerging structural material in the field of earthquake engineering. This paper presents experimental and numerical studies on a scaled self‐centering steel frame with novel SMA braces (SMAB), which utilize superelastic Ni–Ti wires. The braces were fabricated and cyclically characterized before their installation in a two‐story one‐bay steel frame. The equivalent viscous damping ratio and ‘post‐yield’ stiffness ratio of the tested braces are around 5% and 0.15, respectively. In particular, the frame was seismically designed with nearly all pin connections, including the pinned column bases. To assess the seismic performance of the SMA braced frame (SMABF), a series of shake table tests were conducted, in which the SMABF was subjected to ground motions with incremental seismic intensity levels. No repair or replacement of structural members was performed during the entire series of tests. Experimental results showed that the SMAB could withstand several strong earthquakes with very limited capacity degradation. Thanks to the self‐centering capacity and pin‐connection design, the steel frame was subjected to limited damage and zero residual deformation even if the peak interstory drift ratio exceeded 2%. Good agreement was found between the experimental results and numerical simulations. The current study validates the prospect of using SMAB as a standalone seismic‐resisting component in critical building structures when high seismic performance or earthquake resilience is desirable under moderate and strong earthquakes. Copyright © 2016 John Wiley & Sons, Ltd.     

建筑物高低层地震反应差异研究

建筑物高低层的地震反应是有差异的.本文对一栋20层钢筋混凝土框架结构进行了平面地震反应分析,并对一栋在汶川大地震中带有器物反应现象的4层钢筋混凝土框架结构进行了三维地震反应分析,得到了各楼层的位移、速度、加速度时程曲线及反应谱曲线.通过对计算结果的分析验证了“随楼层增高,人的感觉和器物的反应越强烈”的现象,初步分析了产...     

Self-centering seismic retrofit scheme for reinforced concrete frame structures: SDOF system study

This paper presents the results of a parametric study of self-centering seismic retrofit schemes for reinforced concrete (RC) frame buildings. The self-centering retrofit system features flag-shaped hysteresis and minimal residual deformation. For comparison purpose,an alternate seismic retrofit scheme that uses a bilinear-hysteresis retrofit system such as buckling-restrained braces (BRB) is also considered in this paper. The parametric study was carried out in a single-degree-of-freedom (SDOF) system framework since a multi-story building structure may be idealized as an equivalent SDOF system and investigation of the performance of this equivalent SDOF system can provide insight into the seismic response of the multi-story building. A peak-oriented hysteresis model which can consider the strength and stiffness degradation is used to describe the hysteretic behavior of RC structures. The parametric study involves two key parameters -the strength ratio and elastic stiffness ratio between the seismic retrofit system and the original RC frame. An ensemble of 172 earthquake ground motion records scaled to the design basis earthquake in California with a probability of exceedance of 10% in 50 years was constructed for the simulation-based parametric study. The effectiveness of the two seismic retrofit schemes considered in this study is evaluated in terms of peak displacement ratio,peak acceleration ratio,energy dissipation demand ratio and residual displacement ratio between the SDOF systems with and without retrofit. It is found from this parametric study that RC structures retrofitted with the self-centering retrofit scheme (SCRS) can achieve a seismic performance level comparable to the bilinear-hysteresis retrofit scheme (BHRS) in terms of peak displacement and energy dissipation demand ratio while having negligible residual displacement after earthquake.