基于ANSYS的带加强层结构的空间有限元分析

利用ANSYS建立的6个空间有限元模型分析了带加强层框筒结构的侧向位移。通过对不同假设下建立的有限元模型的计算得到了框架柱弯曲刚度,普通框架梁等因素在带加强层高层结构抗侧移的贡献情况。讨论了各种计算模型的特点及分析结果的精确性。从三维有限元分析结果看出,在设计带加强层的高层建筑结构时必须用考虑楼层梁和框架柱抗弯作用的计算模型来控制侧向位移。     

加强层对筒中筒结构受力性能的影响研究

随着建筑高度的不断增大,建筑高度与结构刚度之间的矛盾愈发激烈,筒中筒结构及带加强层的筒中筒结构因此而产生。本文基于某实际工程若干模型的有限元分析,探讨了加强层的刚度、位置、数量等的改变对筒中筒结构空间受力的影响。结果表明,加强层的合理设置,可以有效地改善结构的剪力滞后效应,使得结构内力朝着有利的方向进行重分布;对于减少结构侧移而言,在筒中筒结构中设置加强层效果明显不如框架-核心筒结构,在筒中筒结构设置水平刚臂的基础上再设置外框圈梁的作用也不如框架核心筒结构显著;加强层的刚度不宜过大,否则容易使得结构产生薄弱层,不利于结构抗震;当沿着结构高度均匀设置加强层时,可以不考虑加强层的最优位置。基于研究结论,提出筒中筒结构设置加强层的建议。     

框架-核心筒结构耗能减震层的减震效果分析

本文提出了耗能减震层的概念,对比分析了在地震作用下普通框筒结构、带加强层的框筒结构和带耗能减震层的框筒结构的抗震性能和构件的内力变化.计算结果表明,在对结构位移控制效果接近的情况下,采用加强层的结构不仅增大了基底剪力和弯矩,而且框架柱的内力在加强层附近产生突变,而采用耗能减震层能有效地减小这些变化,与前者相比,大大提高了结构的抗震性能.     

带水平加强层的框-筒结构受力分析

对于高层建筑,设置水平加强层,能够非常明显地减小结构在水平荷载作用下的水平位移量,但是加强层的设置能引起结构竖向刚度的突变和结构内力的重分布。文中通过对八种不同加强层设置情况的框架-筒体结构进行详细的计算与分析,详细剖析了水平加强层减少结构侧移、改变结构受力状态的原因。     

伸臂特性对框-筒结构中加强层力学性能的影响

本文根据伸臂结构的简化模型和伸臂与外框柱的变形协调条件,考虑伸臂的实际刚度,导出伸臂对核心墙的附加力矩,求得结构顶点侧移。对伸臂位置及刚度变化引起的侧移变化与内力突变进行了分析,结合工程分析结果对高层建筑加强层设计提出了一些参考意见。     

带穿层柱钢框架结构受力机理研究

为了研究带穿层柱框架结构的受力机理,将穿层柱高度范围的剩余框架视为子结构,采用广义反弯点法(D值法)确定结构的侧向刚度.考虑穿层柱占比、穿层柱高度对结构侧向刚度比、自振周期、构件内力以及层间位移角的影响,给出了实用的评估方法.通过考虑同层框架柱相互作用的影响,合理确定有侧移框架穿层柱的计算长度系数.分别采用静力弹塑性分析与动力弹塑性时程分析对带穿层柱框架结构进行罕遇地震作用分析.计算结果表明:随着穿层柱数量与穿层柱高度增大,结构的侧向刚度比减小,基本自振周期延长,最大层间位移角增大,柱剪力分配显著变化;穿层柱顶楼层框架梁轴力存在突变,该层楼盖在协调结构变形与内力分配方面具有较大作用,在设计时需要适当加强;在确定有侧移框架穿层柱的计算长度时,可考虑同层框架柱相互作用的影响,对穿层柱的计算长度系数进行修正;穿层柱的弹性刚度较小,在罕遇地震作用下进入塑性较晚,故此其分担的剪力显著增大;随着穿层柱数量减少、穿层柱高度增大,塑性阶段剪力分担率增幅加大.提出的基于穿层柱数量与穿越层数的地震力放大拟合计算式,可用于穿层柱塑性阶段剪力占比放大倍数估算.     

超高层建筑设置水平加强层作用分析

以实际工程为例,对超高层建筑利用避难层设置水平加强层这一措施展开讨论.通过改变外筒环粱高度、水平加强层的位置以及水平加强层的竖向弯曲刚度,进行结构分析,总结在侧向力作用下其内力分布规律,进而对钢筋混凝土筒体结构设置水平加强层所能起的作用进行了探讨,在分析和比较的基础上对高层建筑设置水平加强层的条件提出了一些建议,为今后上程设计提供一些资料.     

带水平加强层的框架-筒体结构受力机理分析

水平加强层能够有效地减小高层框架．筒体结构在水平荷载作用下的侧向位移,但加强层的设置能引起结构竖向刚度的突变和结构内力的重分布。通过对四种不同加强层设置情况的框架-筒体结构进行详细的计算与分析,研究水平加强层在改善结构受力状态、减少结构侧移、提高结构整体抗侧刚度的作用机理,为高层框架．筒体结构的设计提供了相关建议。     

梭形超高层筒中筒结构的受力特性分析

拟建于上海的某超高层建筑,立面造型为梭形,结构体系采用了筒中筒结构,根据其特殊的建筑造型,外筒采取了斜柱方案。分析表明,翼框柱的倾斜可以改变结构的侧向刚度和楼层内力的分布,内筒和外筒的腹板框架承担了更大的层内力;结构上部的刚度增加,下部的刚度减小。建议在结构底部适当提高核心筒混凝土墙中钢骨的含骨率,并且把外筒钢柱改成型钢混凝土柱,以提高结构的刚度、承载力和延性。     

某钢管混凝土筒中筒超高层结构设计

某超高层地下2层、地上79层,顶部68～79层逐层内收,桅杆顶高度为339m。采用了带加强层的"矩形钢管混凝土柱外筒-钢筋混凝土内筒"的筒中筒混合结构体系,为了满足侧移刚度要求,结合设备层和避难层的布置设置了3道结构加强层。介绍了该工程结构选型、抗震性能目标及主要分析结果,采用SATWE,MIDAS Building软件进行了施工阶段模拟分析、多遇地震弹性时程分析和罕遇地震动力弹塑性分析。计算结果表明,该工程安全可靠,能够满足抗震性能设计目标。     

A simplified model for analysis of high‐rise buildings equipped with hysteresis damped outriggers

A simplified model is developed to estimate the seismic response of high‐rise buildings equipped with hysteresis damped outriggers. In the simplified model, the core tube is considered as a cantilever beam, and the effects of outriggers on the core tube are considered as concentrated moments. Modal decomposition method is adopted to obtain the seismic response of the simplified model. To investigate the accuracy and effectiveness of the simplified model, a high‐rise building with a height of 160 m was adopted as the example structure, and its response subjected to a ground motion was analyzed using the simplified model. A corresponding finite element model was built and analyzed by a finite element program called SAP2000 (Computers and Structures, Inc. Berkeley, California, United States). The analysis results obtained from the two models were compared. To consider the randomness of the ground motion, comparisons between the two models were further conducted using another 22 ground motions. It is found that the analysis results obtained from the simplified model agree well with those obtained from the finite element model, and the computation time used for the simplified model is almost negligible compared to that used for the finite element model. Such observations demonstrate that the simplified model is accurate and effective. Copyright © 2013 John Wiley & Sons, Ltd.     

Parameter study of framed‐tube structures with outriggers using genetic algorithm

In this paper, the analysis of optimal locations of framed‐tube structures with outriggers is conducted with the uniform and nonuniform core and peripheral columns using genetic algorithm, aiming to minimize the interstory drift. Also, comparison and difference of the results between the uniform and nonuniform structures are carried out and discussed. Besides, several parameters which influence the behavior of the structure are identified and analyzed, such as different objective functions, segments of outriggers, thickness of core wall, stiffness of outriggers, and grade of concrete strength. In addition, a Matlab program is written to perform the parameter analysis of optimal location of outriggers. Take a 260‐m high‐rise building as a target building, the optimal locations of one to two sets of outriggers subjected to three kinds of horizontal loadings (uniform, parabolic, and triangular) are obtained and can be utilized for the structural preliminary design of tall buildings.     

巨型混合框架-核心筒结构的性能分析

巨型混合框架-核心筒结构是由巨型型钢混凝土框架、混凝土核心筒与伸臂桁架组成的一种具有多道抗震防线的超高层结构体系.为了有效地提高巨型混合框架-核心筒结构的抗侧刚度和内外筒之间的协同工作性能,可采取以下措施:增加巨型梁的刚度;增加伸臂桁架的刚度;增设巨型支撑.分析结果表明:设置跨越两个楼层的巨型梁或伸臂,或增设巨型支撑,...     

A general solution for performance evaluation of a tall building with multiple damped and undamped outriggers

This paper presents a general solution for performance evaluation of a tall building with multiple damped and undamped outriggers. First, general rotational stiffness (GRS) is proposed to model an outrigger that consists of the stiffness of perimeter columns and an outrigger connection and the damping of dampers in an outrigger. By utilizing the dynamic stiffness method, the GRS can be represented by complex stiffness in an outrigger element. To analyze the dynamic characteristics of a tall building with multiple outriggers, a dynamic transcendental equation is obtained from the combination of the GRS and dynamic stiffness method. The structural responses can be calculated through the Fourier transform based on this equation. Moreover, the GRS can also be blended into a finite element (FE) model to generate an augmented state‐space equation for the analysis of the dynamic characteristics and structural responses. Applications to various outriggers are illustrated. In the numerical analysis, good agreements are found between the GRS and the FE that validates the proposed method, and the performances of various outrigger systems are evaluated parametrically. As the results of a tall building with multiple damped or undamped outriggers, the proposed method is capable of providing an optimally parametric design with respect to the position of outriggers, damping, and core‐to‐column and core‐to‐outrigger stiffness ratio. Copyright © 2015 John Wiley & Sons, Ltd.     

Analysis of a high‐rise steel structure with viscous damped outriggers

Damped outriggers for tall buildings draw increasingly attentions to engineers. With a shaking table test, two models of a high‐rise steel column‐tube structure are established, one with outriggers fixed to the core and hinged at the columns, whereas the other's cantilevering outriggers are connected to columns by viscous dampers. According to their dynamic properties, five earthquake waves are selected from the Ground Motion Database of Pacific Earthquake Engineering Research Center (PEER), and two artificial waves are generated by software SIMQKE_GR. Under various peak ground accelerations (PGAs), nonlinear time‐history analysis is applied to compare structural elastic seismic responses, including accelerations, inter‐story drifts, base shear force, damper's response and additional damping ratios. It is concluded that under minor earthquakes, accelerations, inter‐story drifts and base shear force of structure with damped outriggers are larger than or nearly equal to those of the one with fixed outriggers, and the viscous dampers hardly work. But as PGA increases, the contrary situation happens, and the effect of viscous dampers is enhanced as well. The additional damping ratio reaches around 4% under mega earthquakes. Copyright © 2013 John Wiley & Sons, Ltd.     

位移放大型黏滞阻尼伸臂桁架减震效果及动力试验研究

为提高黏滞阻尼伸臂桁架在地震作用下的耗能效率,设计了一种带位移放大装置的黏滞阻尼伸臂桁架。对分别设置传统型和位移放大型黏滞阻尼伸臂桁架的超高层结构进行有限元分析,对比了结构的地震响应及阻尼器的工作状态。通过动力荷载试验,考察两种黏滞阻尼伸臂桁架的滞回性能,对比阻尼器的位移及耗能,研究位移放大系数的变化规律,分析伸臂桁架刚度对黏滞阻尼伸臂桁架工作效率的影响。结果表明：相比传统型黏滞阻尼伸臂桁架,采用位移放大型黏滞阻尼伸臂桁架可将阻尼器的耗能效率提高至原来的1.5~1.8倍,使结构获得更好的减震效果;位移放大型黏滞阻尼伸臂桁架滞回曲线光滑、对称、饱满,具有良好的工作性能,且能有效放大阻尼器的工作位移并增大耗能;提出了黏滞阻尼伸臂桁架的位移放大系数的计算式,计算值与试验值吻合较好;为保证黏滞阻尼伸臂桁架的工作效率,建议伸臂桁架的刚度比取值不小于9。     

雪莲大厦高层混合结构设计

北京雪莲大厦为地上部分36层,建筑总高度146.30m的高层建筑,结构具有以下特点:结构高度高,地震反应大,平面轮廓不规则,在纵横两个方向的框架不正交,不能形成有效的抗侧力体系。为解决这些问题,设计中采取了以下措施:采用由矩形钢管混凝土框架-钢筋混凝土核心筒组成的混合结构体系,并设了两个加强层,有效地加强了结构的刚度,采用矩形钢管混凝土框架则解决了框架不正交所带来的梁柱连接问题。介绍了该工程结构体系的选择,加强层的设计及型钢梁柱节点的处理等,工程实践表明:在高烈度区,带加强层的混合结构体系能够满足结构各项设计要求;矩形钢管混凝土柱可大大减少柱断面,也便于非正交框架体系中梁柱的连接。     

超高层建筑结构加强层耗能减震技术及连接节点设计研究

在框架-核心筒结构体系中,加强层可显著提高结构抗侧刚度、减小结构侧移,但会带来结构刚度、内力突变等不利影响。以某超高层建筑为工程背景,研究了黏滞阻尼器在伸臂桁架体系中的应用及在多遇地震和罕遇地震作用下的减震效果,研究了设置黏滞阻尼器的环带桁架在超高层建筑中的较优位置和减震效率。结果表明：黏滞阻尼器在伸臂桁架结构中的设置可以减小核心筒剪力墙的塑性损伤,减小结构的动力响应;设置黏滞阻尼器的环带桁架宜布置在层间相对速度大的位置,随超高层结构高度增加,阻尼器的减震效率降低。通过对伸臂桁架与外框柱、核心筒连接节点的设计及构造的分析,提出了连接节点的设计建议。     

伸臂刚度对加强层设置位置的影响分析

根据伸臂结构的简化模型和伸臂与外框柱的变形协调条件,考虑伸臂的实际刚度,导出伸臂对核心墙的附加力矩,求得结构顶点侧移。对伸臂位置变化引起的侧移变化与内力突变进行了分析,结合工程分析结果对高层建筑加强层设计提出了一些参考意见。     

中国国际丝路中心超高层结构设计与关键技术

中国国际丝路中心超高层建筑总高度498 m,位于陕西省西安市,抗震设防烈度8度,该结构的侧向变形和承载力均由地震作用控制。为解决结构侧向刚度不足的问题,设置了伸臂桁架加强层,然而传统伸臂桁架往往会造成结构刚度和承载力突变等问题。为此,采用基于刚性伸臂和黏滞阻尼伸臂的组合伸臂桁架技术,研究刚性伸臂桁架和黏滞阻尼伸臂桁架在结构中的较优布置位置和实际效果,从结构指标、结构耗能、构件受力及经济性等方面进行了综合对比。提出了在结构上部两个避难区布置黏滞阻尼伸臂桁架,在结构下部两个避难区布置刚性伸臂桁架的布置方式。从结构响应和结构损伤方面,分析了结构在不同水准地震作用下的抗震性能,并对结构伸臂桁架关键节点进行了有限元分析。结果表明：通过采用组合伸臂桁架技术,可使结构耗能机制得到改善,结构地震响应和构件损伤得到降低,且伸臂桁架安全可靠。