Technological Advances in Japan’s High-Rise Buildings

The architectural and structural analysis of selected high-rise buildings in Japan is presented in this paper. Tokyo, Osaka and Nagoya have the largest share in development of high-rise buildings. Those cities are very densely populated and moreover they are located in one of the most active seismic zones. The combination of these factors has resulted in the creation of sophisticated designs and innovative engineering solutions, especially in the field of design and construction of high-rise buildings. The foreign architectural studios (Jean Nouvel, Kohn Pedesen Associates, Skidmore, Owings & Merrill) which specialize in the designing of skyscrapers, played a major role in the development of technological ideas and architectural forms for such extraordinary engineering structures. Among the projects completed by them, there are examples of high-rise buildings that set precedents for future development. An essential aspect which influences the design of high-rise buildings is the necessity to take into consideration their dynamic reaction to earthquakes and counteracting wind vortices. The need to control motions of these buildings, induced by the force coming from earthquakes and wind, led to the development of various methods and devices for dissipating energy during such phenomena. Currently, Japan is a global leader in seismic technologies which safeguard seismic influence on high-rise structures. Due to these achievements the most modern skyscrapers in Japan are able to withstand earthquakes with a magnitude of over seven degrees at the Richter scale. Applied damping devices applied are of a passive type, which do not require additional power supply or active type which need the input of extra energy. In recent years also hybrid dampers were used, with an additional active element to improve the efficiency of passive damping.W artykule przedstawiono analizę architektoniczną i konstrukcyjną wybranych budynków wysokich w Japonii. Tokio, Osaka i Nagoya mają największy udział w rozwoju wieżowców. Miasta te są bardzo gęsto zaludnione, a ponadto znajdują się w jednej z najbardziej aktywnych stref sejsmicznych. Połączenie tych czynników spowodowało powstanie wyrafinowanych projektów i innowacyjnych rozwiązań inżynierskich szczególnie w dziedzinie projektowania i wznoszenia budynków wysokich. Duży udział w rozwoju myśli technologicznej i formy architektonicznej miały zagraniczne biura architektoniczne (Jean Nouvel, Kohn Pedesen Associates, Skidmore, Owings & Merill) specjalizujące się w projektowaniu wieżowców. Wśród zrealizowanych przez nich projektów, które są przedmiotem analizy znajdują się przykłady wysokich budynków, wyznaczających precedensy dla przyszłego rozwoju. Niezbędnym aspektem projektowania dla wysokich budynków jest dynamiczna reakcja na trzęsienia ziemi i przeciwdziałanie wirom wiatru. Potrzeba sterowania ruchem doprowadziła do opracowania różnych metod i urządzeń do rozpraszania energii. Obecnie Japonia jest światowym liderem w technologiach sejsmicznych. Najnowocześniejsze wieżowce w Japonii są w stanie przetrwać wstrząsy o sile ponad siedem stopni w skali Richtera. Stosowane urządzenia tłumiące są pasywne, które nie wymagają dodatkowego zasilania energią, albo aktywne (AMD), co tłumi reakcję za pomocą energii wejściowej. W ostatnich latach stosuje się tłumiki hybrydowe, z dodatkowym elementem aktywnym, który ma na celu poprawienie skuteczności działania tłumienia pasywnego

Strategies for mitigating wind-induced motion in tall buildings through aerodynamic and damping modifications

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 50-55).The advent of modern structural systems, spurred by advances in construction methodology and high strength materials, has driven the height of modern skyscrapers beyond what was once deemed possible. Although science and technology has been able to increase the strength of building materials such as steel and concrete, their material stiffness has remained virtually unchanged. The end result is a wave of taller, slender and more flexible skyscrapers that are very susceptible to wind-induced excitations. Ever mindful of the fact that human comfort levels are affected by perceived structural responses, engineers must employ various strategies to satisfy serviceability constraints. This thesis presents an overview, in addition to successful applications, of the various aerodynamic and damping modifications that are used to control wind-induced motion in tall buildings. Finally, a modified gyrostabilizer, akin to those used in luxury yachts, is proposed as a possible active control mechanism. The feasibility of this device was studied using simple statics and rigid body dynamics.by Nnabuihe Nnamani.M.Eng

Passive, semi-active, active and hybrid mass dampers: A literature review with associated applications on building-like structures

In this paper, a state-of-the-art literature review is presented emphasising on the development of control variants for mass damper schemes on building-like structures. Additionally, a systematic literature review is conducted addressing three relevant questions: What type of mass damper is preferable by the associated industry? How are mass dampers distributed around the world? Is industry following research? Through the systematic literature review, updated lists of mass damper implementations and control algorithm applications in real-life structures were compiled. 208 case-studies are discussed in total. It is found that, 63% of them refer to passive tuned mass dampers, 31% to hybrid mass dampers, 4.0% to active mass dampers and only 2% to semi-active mass dampers. Regarding control algorithms, controllers of 24 structures driving semi-active, active or hybrid mass dampers are presented. It is concluded that the industry considerably lags behind latest structural control research both regarding implementations and overall management

Semi-active control of structures using current-controlled MR fluid damper

University of Technology, Sydney. Faculty of Engineering and Information Technology.A critical aspect of the design of smart structures for buildings and other civil engineering infrastructure is the reduction of vibrations, deflections and forces induced by external disturbances such as earthquakes, strong winds or heavy dynamic loads. This research work focuses on the design of a second-order sliding mode controller for vibration control using Magneto-rheological fluid (MR) dampers integrated in smart structures to sustain external earthquakes or dynamic loadings. Following comprehensive surveys on structural control and recent earthquakes scenarios around the globe, this work presents an effective control system for suppression of structural vibrations. The advantages of these structures come from the use of semiactive devices for the fail safe operations and low energy consumption. MR dampers are increasingly employed in structural control applications owing to many feasible advantages for mitigation of dynamic effects caused by external disturbances. However, the control of MR dampers is hindered by their nonlinear force-displacement and hysteresis force-velocity responses which usual1y affect controllability. On the other hand, the required yielding force to suppress structural vibrations results from the magnetisation of the fluid particle suspension in the damper housing via the controlled current. To robustly control the dampers' magnetisation current, the sliding mode methodology is adopted. In the context of structural control, a sliding mode controller is an attractive candidate for semiactive control of quake-induced structures in face of uncertainties. In most of MR damper controllers developed so far, the damping force is quite often derived as the control signal, while the damper current is obtained via a secondary current-control loop. In this study, the controlled current for MR-dampers is directly generated by using second-order sliding mode controllers with the aims to satisfy the control constraints, retain strong robustness and remove chattering. The higher-order sliding mode idea is to drive to zero not only the sliding function of the state variables but also higher-order time derivatives of the sliding function. The effectiveness of the second-order sliding mode controller is verified, in simulation, on a benchmark three storey building models subject to excitation of various scaled earthquake records

Passive and Semi-Active Structure-Multiple Tuned Liquid Damper Systems

The resonant vibration motion of tall buildings due to dynamic loading, such as wind storms and earthquakes, can be reduced by adding passive dynamic vibration absorbers (DVAs). A single sway mode of vibration is usually considered, however, for certain structures, multiple modes may need to be suppressed. Furthermore, the location of the TLD on the floor plate is important for certain modes, such as the torsional mode. As a result, a three dimensional finite element structure-TLD system model capable of dynamically analyzing a 3D structure is developed and validated. Two different nonlinear TLD models are considered. A full dynamic analysis of a 3D single-story structure-TLD system is carried out utilizing the two TLD models and results under harmonic and random excitation are compared with experimental values. The three dimensional finite element structure-tuned liquid damper system model (3D-Structure-TLD) is expanded to include multiple tuned liquid dampers (3D-Structure-MTLD) and employed to estimate the response of a full-scale model of a 38-story multi-modal high-rise building subjected to wind tunnel loads recorded at different locations along the building’s width and height. To further improve TLD effectiveness, the nonlinear TLD fluid model is modified in order to simulate the influence of inclined damping screens. The updated passive TLD model is used to investigate the performance of both a single-story structure-TLD system and a 38-story structure-MTLD system with inclined damping screens over a range of structural response amplitudes utilizing random excitation and wind tunnel loads, respectively. Thus, the methodology to optimize the effective damping provided by the TLD over a range of structural responses is addressed. Finally, a control strategy based on gain scheduling scheme is developed, by actively controlling the damping screen inclination angle. The updated nonlinear fluid model of a TLD equipped with inclined damping screens is used to determine the resulting TLD base shear force and free surface response of a novel semi-active (SA) TLD. The semi-active TLD control technique is also expanded to include semi-active multiple TLDs (3D-Structure-SA-MTLD) and employed to analyze a 38-story building over a range of wind angles and return periods. The improved performance of a semi-active TLD system over a passive TLD system is addressed

Effects of a tuned mass damper on wind-induced motions in tall buildings

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 104-107).With ever increasing constructability capacities, engineers have found solutions to build taller and taller structures. However, the race for the sky has not only brought up new ways of building, it has also created new problems to face, namely wind-induced motions. In particular, wind loadings are now the source of vibrations in buildings, which have a direct impact on users. While in the past, strength capacities were the main concern, nowadays, human's comfort has become the one of the new primary problems engineers have to face when designing skyscrapers. Several solutions have been developed throughout the years in order to mitigate the response of a building to wind loads, one of which is the Tuned Mass Damper system. This system, which consists of an auxiliary mass added to a structure, significantly reduces motions in high-rise buildings. However, the theory is often based on a harmonic excitation of a building, which is not necessarily the exact representation of wind loads. This paper analyzes the effects of a Tuned Mass Damper on the response of a building to a saw tooth excitation with white noise, which seems to be a better approximation of how wind loads act on tall structures.by Julien Carlot.M.Eng

Seismic response control of structures using novel adaptive passive and semi-active variable stiffness and negative stiffness devices

Current seismic design practice promotes inelastic response in order to reduce the design forces. By allowing the structure to yield while increasing the ductility of the structure, the global forces can be kept within the limited bounds dictated by the yield strength. However, during severe earthquakes, the structures undergo significant inelastic deformations leading to stiffness and strength degradation, increased interstory drifts, and damage with residual drift. The research presented in this thesis has three components that seek to address these challenges. To prevent the inelastic effects observed in yielding systems, a new concept “apparent weakening” is proposed and verified through shake table studies in this thesis. “Apparent weakening” is introduced in the structural system using a complementary “adaptive negative stiffness device” (NSD) that mimics "yielding” of the global system thus attracting it away from the main structural system. Unlike the concept of weakening and damping, where the main structural system strength is reduced, the new system does not alter the original structural system, but produces effects compatible with an early yielding. Response reduction using NSD is achieved in a two step sequence. First the NSD, which is capable of exhibiting nonlinear elastic stiffness, is developed based on the properties of the structure. This NSD is added to the structure resulting in reduction of the stiffness of the structure and NSD assembly or “apparent weakening”-thereby resulting in the reduction of the base shear of the assembly. Then a passive damper, designed for the assembly to reduce the displacements that are caused due to the “apparent weakening”, is added to the structure-thereby reducing the base shear, acceleration and displacement in a two step process. The primary focus of this thesis is to analyze and experimentally verify the response reduction attributes of NSD in (a) elastic structural systems (b) yielding systems and (3) multistory structures. Experimental studies on 1:3 scale three-story frame structure have confirmed that consistent reductions in displacements, accelerations and base shear can be achieved in an elastic structure and bilinear inelastic structure by adding the NSD and viscous fluid damper. It has also been demonstrated that the stiffening in NSD will prevent the structure from collapsing. Analogous to the inelastic design, the acceleration and base shear and deformation of the structure and NSD assembly can be reduced by more than 20% for moderate ground motions and the collapse of structure can be prevented for severe ground motions. Simulation studies have been carried on an inelastic multistoried shear building to demonstrate the effectiveness of placing NSDs and dampers at multiple locations along the height of the building; referred to as “distributed isolation”. The results reported in this study have demonstrated that by placing a NSD in a particular story the superstructure above that story can be isolated from the effects of ground motion. Since the NSDs in the bottom floors will undergo large deformations, a generalized scheme to incorporate NSDs with different force deformation behavior in each storey is proposed. The properties of NSD are varied to minimize the localized inter-story deformation and distribute it evenly along the height of the building. Additionally, two semi-active approaches have also been proposed to improve the performance of NSD in yielding structures and also adapt to varying structure properties in real time. The second component of this thesis deals with development of a novel device to control the response of structural system using adaptive length pendulum smart tuned mass damper (ALP-STMD). A mechanism to achieve the variable pendulum length is developed using shape memory alloy wire actuator. ALP-STMD acts as a vibration absorber and since the length is tuned to match the instantaneous frequency, using a STFT algorithm, all the vibrations pertaining to the dominant frequency are absorbed. ALP-STMD is capable of absorbing all the energy pertaining to the tuned-frequency of the system; the performance is experimentally verified for forced vibration (stationary and non-stationary) and free vibration. The third component of this thesis covers the development of an adaptive control algorithm to compensate hysteresis in hysteretic systems. Hysteretic system with variable stiffness hysteresis is represented as a quasi-linear parameter varying (LPV) system and a gain scheduled controller is designed for the quasi-LPV system using linear matrix inequalities approach. Designed controller is scheduled based on two parameters: linear time-varying stiffness (slow varying parameter) and the stiffness of friction hysteresis (fast varying parameter). The effectiveness of the proposed controller is demonstrated through numerical studies by comparing the proposed controller with fixed robust H∞ controller. Superior tracking performance of the LPV-GS over the robust H∞ controller in different displacement ranges and various stiffness switching cases is clearly evident from the results presented in this thesis. The LPV-GS controller is capable of adapting to the parameter changes and is effective over the entire range of parameter variations

Dynamic interrelationship between technology and architecture in tall buildings

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Architecture, 2005.Page 230 blank.Includes bibliographical references (p. 225-229).The interrelationship between the technology and architecture of tall buildings is investigated from the emergence of tall buildings in the late 19th century to the present. Through the historical research, a filtering concept is developed - original technology and remedial technology - through which one can clearly understand the interrelationship between the technological evolution and architectural esthetic and further stylistic transition of tall buildings. More desirable visions for the future can be constructed based on this concept. Contemporary design practice of tall buildings is reviewed, and design guidelines are provided for new design trends. Investigated in depth are the behavioral characteristics and design methodology for diagrid structures, which emerge as a new direction in the design of tall buildings with their powerful structural rationale and symbolic architectural expression. Moreover, new technologies for tall building structures and facades are developed for performance enhancement through design integration, and their architectural potentials are explored. Special emphasis is placed on the research on the structural dynamic motion control using double skin facades / distributed tuned mass dampers. Design integration among architecture-related disciplines is emphasized throughout the research process as a means to more effectively overcome or at least minimize contemporary technological limitations and to create architecture of higher quality.(cont.) While each study makes its own contribution theoretically and in a particular design situation, from a wider viewpoint, the contribution of this thesis is to create more constructive relationships of architecture-related disciplines to produce better architecture through synergistic effects.by Kyoung-Sun Moon.Ph.D

Mass Inertia Effect Based Vibration Control Systems for Civil Engineering Structure and Infrastructure

This chapter introduces some recent research works carried out in the Blast Resistance and Protective Engineering laboratory of Harbin Institute of Technology (HIT-BRPE) during the past few years. The EMD control system is shown to be effective and feasible for vibration control of civil engineering structures subjected to, such as earthquake, excitations. The DDVC based AMD control system is suitable for low frequency vibration and motion control. The innovative passive TRID system is applicable for rotation and swing motion control, whereas linear TMD system is shown to be invalid for structural swinging motion. All of the control systems mentioned in this chapter, whatever active or passive or hybrid, have a common characteristic, which is to utilize the mass inertia effect either to provide counter force support for functioning of actuator, e.g. AMD subsystem, or to provide gyrus or rotary inertia for anti-swinging motion of suspended structure. Traditionally, these systems have been called Active Mass Damper/Driver (AMD) or Tuned Mass Damper (TMD), herein we want to emphasize the mass inertia effect and its functions. The basic is to be a necessary component of a control system, and more important is its way of working in the subsystem