复杂高层建筑抗震与消能减震研究进展

复杂高层建筑的震害在近来的历次地震中都有发生,其抗震分析和设计难度较大,提高其抗震性能是当前建筑抗震的难点之一。通过对近10年来国内在复杂高层建筑抗震方面的研究进行回顾和总结,重点介绍了组合剪力墙及筒体结构、钢管混凝土结构、结构模型振动台试验和三种消能减震方法。提出了采用新型高效的结构体系及高性能抗震部件或消能减震新技术改善复杂高层建筑抗震性能。这些研究工作与工程实践紧密结合,大部分研究成果已在实际工程中成功应用。图18参28     

A review of the diagrid structural system for tall buildings

Unlike vertical columns of traditional structure, diagrid structural systems for tall buildings have special inclined columns. Due to the inclined columns, a diagrid structural system for tall buildings produces axial force along the column direction under horizontal load, which has the advantage of resisting horizontal wind load and seismic load and gives more freedom to architectural design, so a diagrid structural system for tall buildings becomes an effective new structure style for tall and super‐tall buildings. Theories and tests regarding the diagrid structural system for tall buildings have been intensely researched since the exterior tube of diagrid structural system for tall buildings was first proposed by Torroja in his seminal book. At present, studies for mechanical characteristics, joint form, theories, and tests have been systematized. This paper systematically summarizes existing research achievements of the diagrid structural system for tall buildings and confirms that the structure has larger lateral stiffness and good seismic performance. Based on the favourable performance of concrete‐filled steel tubes, this paper advises the use of concrete‐filled steel tube columns as the columns in diagrid structural systems for tall buildings.     

Optimal vertical configuration of combined energy dissipation outriggers

The damped outrigger system emerged as an improvement of the conventional outriggers with the aim to provide supplemental damping and to contribute to the vibration control in super tall buildings where this system is usually applied. In addition to viscous dampers (VDs), buckling‐restrained braces (BRBs) have also been employed as energy dissipating members in outriggers. Nevertheless, the combined use of outriggers with VDs and BRBs in the same structure has not yet been studied. Such combination can contribute to achieve an effective multiperformance design of super tall buildings. This paper presents a study whose main objective was to determine the optimal vertical combination of two types of energy dissipation outriggers to control the seismic responses of a 9‐zone super tall model structure. Outriggers with VDs (OVDs) and outriggers with BRBs (OBRBs) were placed at the different zones of the structure considering all the possible combinations and in configurations of up to four outriggers. The effects of these combinations on the seismic performance of the structure were studied through parametric analysis and optimization methods. This form of the outrigger system is defined in this paper as combined energy dissipation outrigger system. The results indicate that when two energy dissipation outriggers are used, the combination of OBRB plus OVD shows superior seismic performance compared with other double‐outrigger configurations. In addition, the results show that the locations of OVDs and OBRBs play an important role in the structure behavior; it was found that it is more beneficial to place OBRBs above OVDs.     

Utilization of high-strength concrete in tall buildings

Since 1988, the utilization of high strength concrete has increased owing to the development of tall buildings in many cities of China. High strength concrete is usually used for columns; the advantages are saving floor area and providing better seismic behavior. Composite columns are also adopted under heavily loaded conditions. In this paper, the design of two representative tall buildings in Beijing are briefly introduced.     

我国高层建筑抗震设计的若干问题

回顾与分析了我国高层建筑的发展;讨论了我国高层建筑结构抗震设计的几个问题：材料与结构体系,构件变形能力与轴压比,弹塑性时程分析与弹塑性静力分析,以及基于位移的抗震设计。     

超限高层建筑结构基于性能抗震设计的研究

基于性能的设计方法已引起工程界的关注 ,在超限高层建筑的结构抗震设计中 ,采用基于性能要求的抗震设计方法 ,有助于提高高层建筑工程抗震设计的可靠性、避免抗震安全隐患 ,同时又促进高层建筑技术发展。本义阐述基于性能抗震设计方法与常规抗震设计方法的比较 ;针对超限高层建筑结构的特点 ,提出结构的抗震性能目标、性能水准以及实施性能设计的主要方法 ,包括性能水准判别准则、性能目标的选用及结构计算和试验要求。文中还列举了应用性能设计理念和要求的部分工程实例。     

A multi-objective structural optimization method for serviceability design of tall buildings

Structural optimization design aims to identify optimal design variables corresponding to a minimum objective function with constraints on performance requirements. To this end, many optimization frameworks have been proposed to determine optimal structural systems that are subjected to seismic and wind hazards in isolation. However, some modern tall buildings are sensitive to seismic and wind excitation owing to their complex structural systems and geographic regions. Therefore, a proper structural optimization method for such buildings is required to ensure that the expected performance is achieved in a multi-hazard scenario. This study proposes a multi-objective serviceability design optimization methodology for buildings in multi-hazard seismic and wind environments by combining optimality criteria and the nondominated sorting genetic algorithm II (NSGA-II). Seismic and wind effects can be instantaneously updated due to changes in the structural dynamic properties during the optimal design process. A neural-network-based surrogate model with self-updating is proposed to predict the structural natural frequency so that the overall computation time of the optimization process can be reduced. The proposed method was used to optimize a 50-story frame-tube building and was compared against the general genetic algorithm and general NSGA-II to verify the feasibility and effectiveness.     

带转换层高层建筑结构基于性能的抗震设计

基于性能的设计方法已引起工程界的关注,在带转换层高层建筑结构设计中采用该法有助于提高工程抗震设计的可靠性。本文结合工程实例,就带转换层高层建筑结构的抗震性能目标、性能水准以及实施抗震性能设计的方法作了阐述,为今后类似转换结构设计提供了借鉴。     

中美超限高层建筑性能化抗震设计方法对比分析

为了系统比较中美超限高层建筑基于性能的抗震设计方法,介绍了美国太平洋地震工程研究中心主导实施的“高层建筑推进计划”项目,探讨了该项目的主要成果（PEER-2010）《高层建筑基于性能的抗震设计指南》,并结合算例将其建议的基于性能抗震设计方法与中国GB 50011-2010《建筑抗震设计规范》和GB 50010-2010《高层建筑混凝土结构技术规程》中规定的基于性能抗震设计方法进行对比。研究结果表明:PEER-2010与我国规范中分别建议的超限高层建筑性能化抗震设计方法在性能目标划分、地震动选择、荷载输入及对地基与结构相互作用的考虑上均存在差异。PEER-2010对性能目标的划分相对更宽松,建议的下一代选波方法能够考虑长周期超高层建筑的选波问题,并对考虑地基与上部结构相互作用有着较为明确的规定。     

高层建筑耗能减震新体系概念与实现

本文在分析几种高层建筑结构体系抗震性能不足的基础上,给合当今耗能减震技术的发展,提出了高位转换耗能减震结构体系、带耗能减震层高层结构体系、巨型框架-耗能减震结构体系和天连耗能减震结构体系等几种高层建筑耗能减震结构新体系,并总结了这些耗能减震结构新体系的初步分析研究结果。研究结果表明:这几种新体系能明显改善结构的抗震性能,与传统抗震结构相比具有很好的优越性。最后,提出了这些新体系在实际工程中应用应解决的一些问题。     

华润大厦超限高层的抗震性能化设计

《高层建筑混凝土结构技术规程》(JGJ 3—2010)新增加了第3.11节:结构抗震性能设计,使高层的抗震设防目标有了更进一步的深化和发展。以南宁华润大厦超限高层为工程实例,采用基于性能设计的抗震分析方法,细化了各构件在各阶段的抗震性能目标。采用多种有限元分析软件,针对超限高层详细进行了小震振型反应谱分析、中震作用下的屈服判别法分析、大震作用下的弹塑性静力推覆分析、跨多层通高柱的屈曲分析,并基于分析结果提出了该工程结构的超限抗震加强措施,保证了超限结构的安全可靠,为同类工程设计提供借鉴。     

高层建筑楼板水平地震内力的计算

复杂体形高层建筑,阴角部位的楼板常发生较严重的震害,其抗震分析应该包含楼板水平地震内力的计算。地震区的简单平面高层建筑,哪些情况可以采用装配式楼板,也需要通过楼板接头的抗震强度验算来判定。本文提出“串并联多质点系”力学模型及相应的数学模型,给出在地震作用下高层建筑各层楼板水平变形和内力的通用计算方法。此外,还选取了一定数量的框-墙结构高层建筑实例,对可能影响楼板水平剪力数值的各种因素,进行了系列的地震反应分析。     

RC框架-剪力墙结构的框架地震层剪力分配

我国《建筑抗震设计规范》与《高层建筑混凝土结构技术规程》关于框架-剪力墙结构地震层剪力分配的规定是依据设计经验提出来的,并没有考虑框架与剪力墙各自抗侧刚度比值的影响,因而较为笼统,明显欠缺合理性。连续化分析方法中框架-剪力墙结构的刚度特征值是表征框架-剪力墙受力和变形的重要指标。本文采用静力弹塑性分析（Pushover）方法和动力弹塑性时程分析方法对刚度特征值为1.0～4.5的8栋框架-剪力墙结构进行了全过程研究,得到了多遇、基本和罕遇地震作用下不同刚度特征值的框剪结构楼层剪力分配,以及罕遇地震下剪力墙刚度退化对楼层剪力分配的影响,并给出了框架层剪力分配公式供设计参考。     

不同弹塑性分析软件在超限高层建筑抗震性能分析中的联合应用研究

基于性能的设计方法很难将结构整体与局部关键构件的性能用一种结构分析软件全面把握，联合使用目前成熟的动力弹塑性分析软件PERFORM-3D和ABAQUS，可以利用各自特点对结构的抗震性能进行全面评价。以某超限高层结构为例，首先建立该结构在大震作用下所需达到的抗震性能目标，在PERFORM-3D软件中对整体结构在不同水准下的性能目标直接进行定义，使用ABAQUS软件对关键构件的钢骨、钢筋等局部应力状态进行分析。通过对结构构件性能水准的整体判定和关键构件的局部分析，全面评价了该超限高层结构的抗震性能，从而确定其是否达到预期的抗震性能目标。结果表明，两种软件的联合应用既可以反映结构的整体抗震承载力及抗侧刚度，又能够很好地把握结构关键构件的局部应力状态，可以更为全面且可靠地反映结构的抗震性能。     

关于建筑抗震设计最小地震剪力系数的讨论

介绍了GB 50011-2010《建筑抗震设计规范》关于楼层最小地震剪力系数规定的编写背景,及其与其他国家规范的相关规定的区别。论述了结构的最小地震剪力系数（剪重比）与设防烈度、场地特征周期、结构周期、振型、阻尼比等参数的关系。列举了位于不同地区（沿海和内地）、不同高度的超高层建筑设计,说明由于地震作用和风荷载不同,计算的楼层地震剪力系数、层间位移及墙、柱等构件轴压比也会不同。结构对地震作用与风荷载的反应不同,设计应区别对待。只要设计合理,大多数结构的最小地震剪力系数可以满足规范要求。对一幢超高层建筑结构进行全面剖析,综合比较,论证了各类参数之间的关系,证明我国规范关于楼层最小地震剪力系数的规定不但是必要的,也是合理可行的。     

Variability of seismic demands according to different sets of earthquake ground motions

It is a challenging task to predict seismic demands for earthquake resistant design, particularly for tall buildings. In current seismic design provisions, seismic demands are expressed as a design base shear of which the key components are linear elastic design response spectra, force reduction factor (‘R factor’), and building weight. For tall buildings, response spectrum analysis or response history analysis is recommended in current design provisions. In recent years, new methods for predicting seismic demands have been developed, such as the capacity spectrum method (CSM) and displacement coefficient method. This study investigates the effect of different earthquake ground motion (EQGM) sets on seismic demands. Key components of the base shear and performance points in the CSM are considered as the seismic demands to be tested. For this purpose three EQGM sets are collected independently at rock sites. This study found that seismic demands can vary significantly according to different EQGM sets even though those sets were obtained at sites with similar soil conditions. This study also attempts to provide a criterion for reducing the variability in seismic demands according to different EQGM sets. Copyright © 2007 John Wiley & Sons, Ltd.     

高层建筑钢结构基于风振响应和动力特性的优化设计

高层建筑的风致响应和等效静力荷载虽然可以通过风洞试验和动力分析有效的加以确定,在结构设计的整个过程中这些等效风力却往往被当作常数来应用。本文提出了一个结合气动风力分析和结构刚度优化的自动化技术。在结构设计中利用这个技术,可以在优化结构刚度和最小化结构造价的同时,实时检查和更新作用在建筑结构上的等效风荷载。一个几何尺度与航空研究共同顾问理事会(CAARC)建议的建筑模型一致的钢框架结构被用来进行风力分析和结构优化的例子。结果表明这个技术不但能在满足位移设计要求的情况下优化结构刚度降低造价,而且也降低了作用在结构上的等效风力。     

Numerical study on structural performance of corrugated steel plate shear wall with different yield points steel

As a new type of lateral load-resisting system in SPSW systems, corrugated SPSWs (CSPSWs) have been gradually researched and applied. Corrugated plates offer various advantages over flat plates including higher energy dissipation capacity, ductility, out-of-plane stiffness, and improved buckling stability. For seismic control and isolation techniques, low yield point (LYP) steels (LY100, LY160, and LY225) are the reliable and ideal energy-dissipating materials. The low yield point CSPSWs combine high energy-consuming materials with high-performance structures to provide a better solution for ductile and seismic resistance of high-rise and super tall buildings. Currently, there are no design codes addressing the seismic performance of LYP corrugated steel plate shear walls (CSPSWs). This study investigates cyclic behavior and energy dissipation performance of corrugated steel plate yield point (100, 160, 225, 235, and 345 MPa) of different thickness CSPSWs and determine the plate yield point that provides the optimum performance. Results and findings of this study reveal that compared with the ordinary yield strength corrugated steel plates, the low yield point CSPSWs have a larger safety factor of lateral bearing capacity, a fuller hysteresis curve, a strong energy dissipation coefficient, a larger ductility coefficient and a smaller fluctuation range of strength degradation coefficient, and better strength stability. The initial equivalent stiffness of CSPSWs with different yield strengths is the same.     

Seismic behavior of tall buildings using steel–concrete composite columns and shear walls

For the seismic design of tall building structures, the behavior under severe earthquakes should be carefully considered and the upper limit of inter‐story deformations are often defined by the design codes. To improve the performance of structures under severe earthquakes, composite structural members, including steel reinforced column and steel plate reinforced shear wall, are often adopted. In the present work, the seismic behavior of tall buildings using steel–concrete composite columns and shear walls is investigated numerically. Fiber beam–column element models and multilayer shell models are adopted to establish the finite element model of structure, and the material nonlinearities are described by the plasticity and damage models. The accuracy of the developed models is verified by the experimental results of a single shear wall. Systematic numerical simulations are performed for the tall building structures subjected to different earthquakes. The comparative study indicates that the nonlinear redistribution of internal forces plays a very important role for the performance of tall buildings under severe earthquakes.     

Proposing the hexagrid system as a new structural system for tall buildings

In order to improve the efficiency of tube‐type structures in tall buildings, a new structural system, called hexagrid, is introduced in this paper. In comparison with diagrid system, it consists of multiple hexagonal grids on the face of the building. In this research, a set of structures using diagrid system having four various diagonal angles and hexagrid system were designed on a strength and stiffness‐based approach for buildings with 30, 50, 70 and 90 stories to withstand wind load. The impact of different geometric configurations of structural members on the maximum lateral displacement and architectural performance in both diagrid and hexagrid systems is compared. The stiffness sensitivity using a similar interior bracing system in both systems is also discussed. In this study, the seismic performance of a 30‐story diagrid structure and a hexagrid structure was evaluated using nonlinear static and dynamic analyses. According to the results, the hexagrid system has a better architectural view and more ductility and stiffness sensitivity, which are about three times than that of the diagrid system. And finally, in comparison with the diagrid system, the hexagrid system has enough potential to push the height limit. The guidelines discussed here are for architectural and structural engineers to improve freehand design. Copyright © 2012 John Wiley & Sons, Ltd.