Active Tendon Control of Torsionally Irregular Structures under Near‐Fault Ground Motion Excitation

In this study, torsionally irregular single‐story and multistory structures under the effect of near‐fault ground motion excitation were controlled by active tendons. Near‐fault ground motions contain two impulsive characters. These impulsive characters are the directivity effect perpendicular to fault and the flint step parallel to fault. The structural models were simulated under bidirectional earthquake records superimposed with impulsive motions to examine the response of active control under near‐fault effects. Also, the structures were analyzed only under the effect of bidirectional impulsive pulses. The control signals were obtained by Proportional–Integral–Derivative (PID) type controllers and the parameters of the controllers were obtained by using a numerical algorithm depending on time domain analyses. Time delay effect was also considered for active control system. Different cases of orientation of active tendons were examined and the results of the single‐story structure were compared with another control strategy using frequency domain responses in the optimization process. As a conclusion, the control concept is significantly effective on reducing maximum responses in translational and rotational directions and obtaining a steady‐state response.     

A combined tuned damper and an optimal design method for wind‐induced vibration control for super tall buildings

The wind‐induced vibrations of super tall buildings become excessive due to strong wind loads, super building height and high flexibility. Tuned mass dampers (TMDs) and tuned liquid column dampers (TLCDs) have been widely used to control vibrations for actual super tall buildings for decades. To fully use both the economic advantage of the TLCD system and the high efficiency of the TMD system, an innovative supplemental damping system including both TLCD and TMD and called combined tuned damper (CTD), which can substantially decrease the cost of the damper, was proposed to control the wind‐induced vibrations of tall buildings. The governing equations are generated for the motion of both the primary structure and the CTD and solved to anticipate the dynamic response of the CTD‐structure system. Moreover, an optimal design method of human comfort performance is proposed, in which the life cycle cost of the damper‐structure system is considered as the quantitative index of the performance. The life cycle cost includes the initial cost, the maintenance cost and the failure cost. The failure cost can be calculated using the vibration‐sensation rate model, which is based on the Japanese code AIJES‐V001‐2004. Copyright © 2016 John Wiley & Sons, Ltd.     

Closed form optimal solution of a tuned liquid column damper for suppressing harmonic vibration of structures

Building vibration has become one of the major concerns to structural engineers. Being a vibration absorber, a tuned liquid column damper (TLCD) not only suppresses building vibration, but also acts as the water storage facility of a building. In view of this, the application of such damper is particularly suited for building structures. However, due to inherent nonlinear liquid damping, it is no doubt that a great deal of computational effort is required to search the optimum parameters of TLCD numerically. Therefore, this paper aims to develop a closed form solution scheme of TLCD-structure systems and the optimum parameters of TLCD that lead to the maximum vibration reduction of building structure, so as to facilitate the design of dampers. The developed closed form solution of TLCD-structure system is verified by comparing results obtained from the conventional iterative method. After having a satisfactory verification, the existence of the invariant points of a TLCD-structure system for the case of undamped primary structure is demonstrated. Explicit design formulas of TLCD for the case of undamped primary structures are obtained by optimizing the response at the two invariant points. The optimum parameters of TLCD for the case of damped primary structures are also investigated numerically. An approach for determining the optimum head loss coefficient of TLCD is proposed. Finally, an example is given to illustrate the design procedures of TLCD for suppressing harmonic type vibrations     

Fuzzy‐sliding mode control of nonlinear smart base‐isolated building under earthquake excitation

In this paper, the effectiveness of the fuzzy sliding mode control strategy on three‐dimensional benchmark building with smart base isolation under seismic excitation has been examined. One of the appropriate control theories for such this nonlinear system is the sliding mode control theory; discontinuous sliding mode theory has weakness such as chattering phenomena. In this paper, we used a combination of fuzzy logic and sliding mode theory for the deletion of this defect. The proposed control theory has been scrutinized by applying on lately developed nonlinear three‐dimensional base‐isolated benchmark building. This building because of the three‐dimensional nature, coalescing of lateral and torsional responses, continuity of responses of the superstructure, and base is modeled with three degrees of freedom on every floor. In this building eight actuators assigned only at the base level and in the two directions (x, y). In other words, 16 actuators are located underneath the structure. Furthermore, the base isolation system has been modeled by considering lateral coupled equations for a better examination of the performance of the system. The results indicate that reduction of control performance is remarkable. Also, utilizing proposed control theory can decrease the responses of building in two main directions and, particularly, in the rotational degree of freedom.     

既有多层砌体住宅增设电梯与抗震加固综合改造技术振动台试验研究

我国现有大量建于20世纪七、八十年代的老旧砌体结构住宅,这类住宅材料强度较低,抗震性能较差,大都有抗震加固、增设电梯等结构安全性与建筑功能提升的需求。为避免两项需求单独实施引起的资源浪费,减少入室施工等对房屋正常使用与周边环境的影响,提出了既有多层砌体住宅增设电梯与抗震加固综合改造技术,并制作了一组多层砌体结构缩尺(1∶4)模型,即模型A(未加固的五层无筋砌体结构模型)和模型B(增设电梯、抗震加固综合改造模型),进行了振动台模型对比试验验证。试验结果表明：砌体住宅采用综合改造技术加固后,刚度、基底剪力均有较大幅度提高,结构整体抗震能力明显提高,其脆性破坏的特征亦有显著改善;此外,由于增设的电梯井剪力墙显著增强了结构横向的抗震能力,使得房屋纵、横两个方向的抗震性能趋于均衡,有效地改善了多层砌体结构住宅存在明显抗震强、弱向的自身缺陷。     

Identification of Wind Loads and Estimation of Structural Responses of Super‐Tall Buildings by an Inverse Method

This article presents a Kalman‐filter‐based estimation algorithm for identification of wind loads on a super‐tall building using limited structural responses. In practice, acceleration responses are most convenient to be measured among wind‐induced dynamic responses of structures. The proposed inverse method allows estimating the unknown wind loads and structural responses of a super‐tall building using limited acceleration measurements. Taipei 101 Tower is a super‐tall building with 101 stories and a height of 508 m. Field measurements and numerical simulations of the wind effects on Taipei 101 Tower are conducted. The wind loads acting on the super‐tall building are estimated based on the wind‐induced responses determined from the numerical simulations and the refined finite‐element model of the structure, which are in good agreement with the exact results. The stability performance of the proposed algorithm is evaluated. The influence of noise levels in the measurements and covariance matrix of noise on the identification accuracy are investigated and discussed based on the L‐curve method. Finally, the wind loads and structural responses are reconstructed based on the field‐measured accelerations during Typhoon Matsa. The accuracy of the identified results is verified by comparing the reconstructed acceleration responses with the field measurements. The results of this study show that the proposed inverse approach can provide accurate predictions of the wind loads and wind‐induced responses of super‐tall buildings based on limited measured responses.     

Model‐Based Multi‐input,Multi‐output Supervisory Semi‐active Nonlinear Fuzzy Controller

Abstract: The authors recently proposed a new multi‐input, single‐output (MISO) semi‐active fuzzy controller for vibration control of seismically excited small‐scale buildings. In this article, the previously proposed MISO control system is advanced to a multi‐input, multi‐output (MIMO) control system through integration of a set of model‐based fuzzy controllers that are formulated in terms of linear matrix inequalities (LMIs) such that the global asymptotical stability is guaranteed and the performance on transient responses is also satisfied. The set of model‐based fuzzy controllers is divided into two groups: lower level controllers and a higher level coordinator. The lower level fuzzy controllers are designed using acceleration and drift responses; while velocity information is used for the higher level controller. To demonstrate the effectiveness of the proposed approach, an eight‐story building structure employing magnetorheological (MR) dampers is studied. It is demonstrated from comparison of the uncontrolled and semi‐active controlled responses that the proposed design framework is effective in vibration reduction of a building structure equipped with MR dampers.     

A Decentralized Control Algorithm for Large‐Scale Building Structures

Abstract: Decentralized control strategy is more suitable for structural control of large‐scale structural systems as it increases in the feasibility of control implementation and decreases the risk on the failure of the control system compared with the conventional centralized control approach. In this article, a decentralized control algorithm is proposed for large‐scale linear building structures. A large‐scale building structure is divided into a set of smaller substructures based on its finite element model. Interconnections between adjacent substructures are treated as disturbances to the individual substructure. Each substructure is controlled by its own local controller using linear quadratic Gaussian control scheme with acceleration measurements as feedback signals. A computational procedure is developed for the recursive estimation of the unknown disturbances to each substructure. Two cases, with substructure interface measurement and without substructure interface measurement respectively, are considered. A numerical example of the decentralized control of the 20‐story Structural Engineers Association of California (SAC) benchmark linear building under seismic excitation is studied to evaluate the performance of the proposed algorithm. Simulation results demonstrate that the decentralized control algorithm has quite good control performance compared with the conventional centralized control approach. Therefore, the proposed decentralized control algorithm is viable for structural control of large‐scale linear structural systems.     

Analytical Model for Viscous Wall Dampers

By now, many civil engineering researchers have extensively studied the application of earthquake energy dissipation systems in seismic‐resistant buildings. Earthquake energy dissipation systems play an important role in enhancing the sustainability of structures against seismic excitation. Frame buildings are strengthened by installing damper devices as supplemental structural members. This article presents the finite‐element‐based development of an analytical model for a viscous wall damper (VWD) device, an alternative to other earthquake energy dissipation systems, which can diminish the effect of earthquakes on structures and improve the seismic performance of multistory buildings subjected to ground motion. The constitutive law of VWDs has been formulated and integrated to develop a finite element model of VWD compatible with the reinforced concrete (RC) structure analytical model. Then, the finite element algorithm has been developed for inelastic analysis of RC buildings equipped with VWD devices capable of detecting damage to both structural members and damper connections under dynamic loading. Based on the developed system, the special finite element program was codified and verified by applying it to a real model of a RC building with supplementary VWD devices. Influence of VWDs on seismic performance of the RC building during earthquake excitation was evaluated. The proposed analytical model for VWD is verified by using experimental test data and analysis result proved that this energy dissipation system succeeds by substantially diminishing and dissipating a structure's induced seismic responses. Also the parametric study indicated that the damping coefficient is very effective on performance of VWD.     

大型海上风力发电高塔随机最优减震控制

考察了基于结构动力可靠度的调谐液体柱形阻尼器(TLCD)参数优化设计方法,并用于风-地震联合作用及地震作用下海上风力发电高塔系统的随机最优控制。文中,采用Kane动力学-有限元一体化模型,建立了TLCD-结构整体系统方程。基于概率密度演化理论的极值分布方法,给出了基于可靠度的TLCD参数优化设计方法及程序解答。在数值算例中,采用随机谐和函数和物理随机风场模型分别模拟随机地震动和随机风荷载,通过对优化的受控系统进行随机反应分析与可靠度分析,比较了不同控制准则和约束条件下TLCD的减震控制效果。研究表明基于可靠度的随机最优控制方法是可行的。     

Optimal control of structures under earthquake excitation based on the colonial competitive algorithm

The active control of engineering structures is one of the best methods to reduce structural responses under seismic excitation for the best performance of structures. This study presents an effective approach for the optimal control of structures under strong ground motion using the colonial competitive algorithm. The colonial competitive algorithm was developed over the last few years in an attempt to overcome the inherent limitations of traditional optimize method. The colonial competitive algorithm has been applied due to its ideal performance in optimal control problem. The effectiveness and performance of the proposed method have been investigated through two numerical examples for the response control of earthquake‐excited structures. The obtained results have been compared with the Linear Quadratic Regulator (LQR) control algorithm, and the performance of the proposed control approach has been found to be better than the LQR controller. Copyright © 2012 John Wiley & Sons, Ltd.     

Efficient estimation of tuned liquid column damper inerter (TLCDI) parameters for seismic control of base-isolated structures

This paper presents an enhanced base-isolation (BI) system equipped with a novel passive control device composed of a tuned liquid damper and an inerter (TLCDI). With the aim of reducing the seismic response of BI systems, this contribution focuses on the design of the TLCDI providing analytical solutions for the optimal TLCDI parameters, easily implementable in the design phase. The effectiveness of the proposed approach in terms of seismic response reduction and computational gain is validated by comparison with classical numerical optimization techniques. The control performance of two different base-isolated TLCDI-controlled structures is assessed by employing real-ground motion records, and relevant comparisons with both uncontrolled base-isolated structures and equipped with a conventional TLCD are presented.     

双向地震动输入方法对结构时程分析反应的影响

采用时程分析法进行结构反应分析时,若需要考虑双向地震动输入,通常先按照规范要求选择一定数量的单向地震动,然后将这些地震动和相应的另一正交方向的地震动分量组合作为双向地震动。若按照GB 50011—2010中要求,同时对两个方向的地震动进行筛选,则很难选出足够数量的地震动。仅控制了一个方向的地震动反应谱与设计反应谱统计意义上相符,常会导致结构地震反应统计离散性较大。为此,提出一种对两个方向的地震动均进行控制的双向地震动选择方法,该方法可以快速地选出足够数量的符合要求的双向地震动。以多、高层钢筋混凝土框架结构为例,通过对比常规和本文方法所选双向地震动输入下结构反应的差异验证了所提方法的有效性。以70组大样本地震动输入下结构的弹性和弹塑性地震反应为基准,对比了不同地震动输入样本容量时分析结果保证率的差异,并根据对比结果给出弹性和弹塑性时程分析时地震动输入样本容量的建议取值。     

Influence of seismic incident angle on response uncertainty and structural performance of tall asymmetric structure

The estimation of critical seismic response of a structure is complicated in nature due to the uncertain distribution of the internal forces under multidirectional seismic excitations. One of the important concerns inherent to this complication is the uncertainty associated with the final design direction as different seismic directions result in different seismic responses. In this regard, this research provides a detailed examination of (1) response‐to‐response and record‐to‐record variability under varying seismic orientations, (2) quantification of seismic response uncertainties and (3) the seismic performance of asymmetric structure in the context of conservative/nonconservative seismic design. With the mentioned research objectives, a realistic case study asymmetric structure under the influence of varying bidirectional seismic excitations was evaluated. It has been argued in this research that the seismic excitations applied at structure's reference axes are very unlikely to demonstrate maximum response for all response quantities simultaneously, even if it results in a peak response for a particular seismic response quantity. This research is particularly helpful for the critical assessment of directionality influence on asymmetric structures prior to making any decision during thestructural design process. Substantial arguments have been presented to emphasize the inclusion of the investigation of seismic response uncertainty in practical design of critical asymmetric structures.     

单重和多重调谐质量惯容阻尼器控制连体超高层建筑风振响应比较研究

连体超高层建筑因存在强烈的气动干扰,在强风下可能会出现大幅相对振动,调谐质量惯容阻尼器(TMDI)是一种振动控制装置,其惯容器两端的相对加速度较大时,TMDI振动控制效果较好。结合两者各自的特点提出了多重调谐质量惯容阻尼器(MTMDI)控制连体超高层建筑的风振响应,两个TMDI分别控制两栋建筑各自的一阶自振频率。首先建立了MTMDI控制连体超高层建筑风致响应数学模型,然后开展了某连体超高层建筑的刚性模型同步测压风洞试验;最后,基于该数学模型和测压风洞试验结果分析了该连体建筑在分别安装两个和单个TMDI对风振加速度和位移响应的减振效果。研究结果表明：虽然两个TMDI的总质量和总惯容量比单个TMDI相应的参数小,但两者的减振效果基本相同,两者都能有效地减小两栋建筑在各个风向角下的加速度响应,如在270°风向角下,安装TMDI后两栋建筑顶层加速度响应分别减小了37.5%和50.0%;对于位移响应,两者都可以减小高栋建筑的响应,其对低栋建筑在少部分风向角下的减振效果并不理想。     

Practical design issues of tuned mass dampers for torsionally coupled buildings under earthquake loadings

In this study, a new design procedure was developed for reducing the dynamic responses of torsionally coupled buildings, particularly existing buildings, under bilateral earthquake excitations, by incorporating the vibration control effectiveness of passive tuned mass dampers (PTMDs) . Some practical design issues such as the optimal location for installation, movement direction and numbers of PTMD are considered in this study. The optimal parameters of the PTMD system are determined by minimizing the mean square displacement response ratio of the controlled degree of freedom between the building with and without PTMDs. In addition, parametric studies of the PTMD planar position and the detuning effect are undertaken to determine their influence on the response control efficacy. The numerical results from two typical multistory torsionally coupled buildings under bidirectional ground accelerations, recorded at the 1979 El Centro earthquake, verify that the proposed optimal PTMDs are more effective and more robust in reducing the building responses. Copyright © 2007 John Wiley & Sons, Ltd.     

调谐液柱阻尼系统的半主动模糊控制

基于模糊控制理论,提出了一种新的控制策略和相应的算法,以解决结构使用TLCD(Tuned Liquid Col-umn Damper)阻尼器实施半主动控制的动力减振问题。在TLCD半主动控制系统中,液体对结构的反作用主要取决于液流的运动状态,它直接影响着结构的减振效果。由于液体和结构相互作用的复杂性,目前如何确定每一瞬时的液力阻尼系数,使液体运动处于最佳状态,仍是一个十分困难的问题。本研究的重点集中在控制策略的确定和模糊控制理论的应用上。通过液流运动,液体对结构的作用在形式上相当于施加了两个间接力:“液动阻力”和“势力”。根据二者对结构运动有利与否和结构的具体运动过程,确定出了相应的控制策略,并在此基础上发展了模糊控制规则。数值计算采用一个简化为单自由度系统的结构,使用了TLCD阻尼器实施半主动控制。在数值模拟中,一个模拟风作用的组合谐波被用来激励该系统。数值计算结果说明了TLCD半主动控制系统应用模糊控制理论的可行性和有效性。     

Hybrid simulation of a tall building with a double‐decker tuned sloshing damper system under wind loads

This study presents an advanced experimental system, hardware‐in‐the‐loop (HIL), recently referred to as hybrid testing, to validate the effectiveness of a double‐decker tuned sloshing damper (TSD) system with screens applied to a recently constructed tall building. The HIL simulation facilitates a performance analysis of a combined structure‐damper system in which the nonlinear behavior of liquid motion in a TSD is physically modeled, whereas a building system under wind loads that behaves linearly is embedded virtually utilizing a computer model. The scaled model of the TSD is composed of a computer‐controlled system with a shaking table, sensors, and a real‐time communication link. The virtual building system on the computer communicates in real time with the hardware, that is, the physical model of TSD to evaluate on‐the‐fly the performance of a combined building‐TSD system. External excitation including random loading characteristics of winds, waves, or earthquakes can be implemented in HIL to observe the dynamics of the building‐damper system under a host of loading scenarios. An example of a recently completed tall reinforced concrete building with multiple TSDs placed side by side in double‐decker configuration under a suite of external loads and the proposed damping estimation procedure to evaluate the amount of auxiliary damping with TSD for ensuring the TSD design is presented. It examines the habitability of the building in winds and evaluates the effectiveness of the TSD system as well as the efficacy of the first HIL simulation for an actual tall building‐TSD system equipped with screens inside.     

Optimal drift design model for multi‐story buildings subjected to dynamic lateral forces

An optimal drift design model for a linear multi‐story building structure under dynamic lateral forces is presented. The drift design model is formulated into a minimum weight design problem subjected to constraints on stresses, the displacement at the top of a building, and inter‐story drift. The optimal drift design model consists of three main components: an optimizer, a response spectrum analysis module, and a sensitivity analysis module. Using a small example, the validation of the proposed model has been tested by a comparison of optimal solutions. Then, the performance of the optimal drift design model is demonstrated by application to three steel frame structures including a 40‐story building. Various structural responses including lateral displacement and inter‐story drift distributions along the height of the structure at the initial and final design stages are presented in figures and tables. Time‐consuming trial‐and‐error processes related to drift control of a tall building subjected to lateral loads is avoided by the proposed optimal drift design method. Copyright © 2003 John Wiley & Sons, Ltd.     

基于双向拟静力试验的箱型高墩连续刚构桥Pushover 分析

利用双向拟静力试验得到恢复力模型,分别进行了纵桥向和横桥向的Pushover分析,评价了高墩大跨连续刚构桥的抗震性能.首先,以薄壁箱型高墩双向拟静力试验为基础,建立考虑双向地震动作用的恢复力模型;然后,利用该恢复力模型,采用均匀加速度分布、模态分布和考虑高阶模态的模态分布3种加载模型进行高墩和全桥横向和纵向的Pusho...