• 국제초고층학회논문집
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• 제4권1호
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• pp.39-44
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• 2015

This paper presents the structural health monitoring (SHM) of Shanghai Tower. In order to provide useful information for safety evaluation and regular maintenance under construction and in-service condition, a comprehensive structural health monitoring (SHM) system is installed in Shanghai Tower, which is composed of a main monitoring station and eleven substations. Structural responses at different construction stages are measured using this SHM system and presented in this study. Meanwhile, a detailed finite element model (FEM) is created and comparison of results between SHM and FEM is carried out. Results indicate that the time-dependent property of concrete creep is of great importance to structural response and the measured data can be used in FEM updating to obtain more accurate FEM models at different construction stages. Therefore, installation of structural health monitoring system in super-tall buildings could be considered as an effective way to assure structural safety during the construction process.

• 한국공간구조학회논문집
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• 제14권4호
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• pp.97-104
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• 2014

Recently, a concept of damped outrigger system has been proposed for tall buildings. Structural characteristics and design method of this system were not sufficiently investigated to date. In this study, control performance of damped outrigger system for building structures subjected to seismic excitations has been investigated. And optimal design method of damped outrigger system has been proposed using multi-objective genetic algorithm. To this end, a simplified numerical model of damped outrigger system has been developed. State-space equation formulation proposed in previous research was used to make a numerical model. Multi-objective genetic algorithms has been employed for optimal design of the stiffness and damping parameters of the outrigger damper. Based on numerical analyses, it has been shown that the damped outrigger system control dynamic responses of the tall buildings subjected to earthquake excitations in comparison with a traditional outrigger system.

• Structural Engineering and Mechanics
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• 제47권6호
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• pp.791-818
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• 2013

The seismic performance of reinforced concrete (RC) frame structures with irregularities leading to soft first floor is studied using capacity assessment procedures. The soft first story effect is investigated for the cases: (i) slab-column connections without beams at the first floor, (ii) tall first story height and (iii) pilotis type building (open ground story). The effects of the first floor irregularity on the RC frame structure performance stages at global and local level (limit states) are investigated. Assessment based on the Capacity Spectrum Method (ATC-40) and on the Coefficient Method (FEMA 356) is also examined. Results in terms of failure modes, capacity curves, interstory drifts, ductility requirements and infills behaviour are presented. From the results it can be deduced that the global capacity of the structures is decreased due to the considered first floor morphology irregularities in comparison to the capacities of the regular structure. An increase of the demands for interstory drift is observed at the first floor level due to the considered irregularities while the open ground floor structure (pilotis type) led to even higher values of interstory drift demands at the first story. In the cases of tall first story and slab-column connections without beams soft-story mechanisms have also been observed at the first floor. Rotational criteria (EC8-part3) showed that the structure with slab-column connections without beams exhibited the most critical response.

• Advances in Computational Design
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• 제5권1호
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• pp.35-54
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• 2020

One of the prevailing structural systems in high-rise buildings is the core-wall system. On the other hand, the existence of one or more underground stories causes the perimeter below-grade walls with the diaphragm of grade level to constitute of a very stiff box. In this case or a similar situation, during the lateral response of a tall building, underground perimeter walls and diaphragms that provide an increased lateral resistance relative to the core wall may introduce a prying action in the core that is called backstay effect. In this case, a rather great force is generated at the diaphragm of the grade-level, acting in a reverse direction to the lateral force on the core-wall system, and thus typically causes a reverse internal shear. In this research, in addition to review of the results of the preceding studies, an improved relationship is proposed for prediction of backstay force. The new proposed relationship takes into account the effect of foundation flexibility and is presented in a non-dimensional form. Furthermore, a specific range of the backstay force to lateral load ratio has been determined. And finally, it is shown that although all suggested formulas are valid in the elastic domain, yet with some changes in the initial considerations, they can be applied to some certain non-linear problems as well.

• 한국공간구조학회논문집
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• 제18권2호
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• pp.35-42
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• 2018

The outrigger damper system is a structural system with excellent lateral resistance when a wind load occurs. However, research on outrigger dampers is still in its infancy. In this study, dynamic response control performance of damper is analyzed according to change of stiffness value and damping value of damper. To do this, a real-scale 3D model of 50 stories has been developed and the artificial wind load has been entered for dynamic analysis. Generally, the larger the damping value, the smaller the stiffness value is, the more effective it is to reduce the maximum displacement and acceleration response. However, the larger the attenuation value as the cost of construction increases, it is necessary to select appropriate stiffness and damping value when applying an outrigger damper.

• 국제초고층학회논문집
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• 제10권2호
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• pp.149-164
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• 2021

Most of high-rise buildings in Japan^*1 are structure with damping systems recently. The design procedure is performance-based design (PBD), which is based on the nonlinear response history procedure (NRHP) using 2 or 3-dimentional frame model. In addition, hysteretic property of steel plates or velocity-dependent property of viscous dampers are common practice for the damping system. However, for the selection of damping system, the easy dynamic analysis of recent date may lead the most of engineers to focus attention on the maximum response only without thinking how it shakes. By nature, the seismic design shall be to figure out the action of inertia forces by complex & dynamic loads including periodic and pulse-like characteristics, what we call seismic ground motion. And it shall be done under the dynamic condition. On the contrary, we engineers engineers have constructed the easy-to-use static loads and devoted ourselves to handle them. The structures with damping system shall be designed considering how the stiffness & damping to be applied to the structures against the inertia forces with the viewpoint of dynamic aspect. In this paper we reconsider the role of damping in vibration and give much thought to the basic of shake with damping from a standpoint of structural design. Then, we present some design examples based on them.

• 국제초고층학회논문집
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• 제5권3호
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• pp.233-241
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• 2016

This paper describes the structural solution for the design of a 29-story high-rise tower, which features a large office space above the Kabukiza Theatre. Kabuki is a type of Japanese traditional drama, and Kabukiza is the home building of Kabuki. GINZA KABUKIZA is the fifth generation of the Kabukiza Theatre, the first of which was built in 1889. In order to support 23 stories of office space above the theater - featuring a large void in plan - two 13-meter-deep mega-trusses, spanning 38.4 meters, are installed at the fifth floor of the building. Steelwork is used as a primary material for the structure above-ground, and a hybrid response control system using a buckling-restrained brace and oil damper is adopted in order to achieve a high seismic performance. This paper also describes the erection process of installing hydraulic jacks directly above the mega-truss at column bases, in order to keep the structure above the truss level during construction. The temple architecture of the previous Kabukiza is carefully restored by incorporating contemporary light-weight materials supported by steelwork.

• 국제초고층학회논문집
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• 제2권3호
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• pp.257-269
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• 2013

This study presents the development of an advanced multiple database-enabled design module for high-rise buildings (DEDM-HR), which seamlessly pools databases of multiple high frequency base balance measurements from geographically dispersed locations and merges them together to expand the number of available building configurations for the preliminary design. This feature offers a new direction for the research and professional communities that can be utilized to efficiently pool multiple databases therefore expanding the capability of an individual database and improving the reliability of design estimates. This is demonstrated, in this study, by the unprecedented fusion of two major established databases, which facilitates interoperability. The DEDM-HR employs a cyberbased on-line framework designed with user-friendly/intuitive web interfaces for the convenient estimation of wind-induced responses in the alongwind, acrosswind and torsional directions with minimal user input. In addition, the DEDM-HR embeds a novel feature that allows the use of wind characteristics defined in a code/standard to be used in conjunction with the database. This supplements the provisions of a specific code/standard as in many cases guidance on the acrosswind and torsional response estimates is lacking. Through an example, results from several international codes and standards and the DEDM-HR with the embedded features are compared. This provision enhances the scope of the DEDM-HR in providing an alternative design tool with nested general provisions of various international codes and standards.

• 한국공간구조학회논문집
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• 제19권3호
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• pp.33-40
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• 2019

A seismic isolation system is one of the most effective control devices used for mitigating the structural responses due to earthquake loads. This system is generally used as a type of base isolation system for low- and mid-rise building structures. If the base isolation technique is applied to high-rise buildings, a lot of problems may be induced such as the movement of isolation bearings during severe wind loads, the stability problem of bearings under large compression forces. Therefore, a mid-story isolation system was proposed for seismic protection of high-rise buildings. Residence-commerce complex buildings in Korea have vertical irregularity because shear wall type and frame type structures are vertically connected. This problem can be also solved by the mid-story isolation system. An effective analytical method using super elements and substructures was proposed in this study. This method was used to investigate control performance of mid-story isolation system for residence-commerce complex buildings subjected to seismic loads. Based on numerical analyses, it was shown that the mid-story isolation system can effectively reduce seismic responses of residence-commerce complex tall buildings.

• Structural Engineering and Mechanics
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• 제86권1호
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• pp.29-48
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• 2023

Pounding happens when contiguous structures with differing heights vibrate out of line caused by a seismic activity. The situation is aggravated due to the insufficient separation gap between the structures which can lead to the crashing of the buildings or total collapse of an edifice. Countries around the world have compiled building standards to address the pounding issue. One of the strategies recommended is the introduction of the separation gap between structures. AS1170.4-2007 is an Australian standard that requires 1% of the building height as a minimum separation gap between buildings to preclude pounding. This article presents experimental and numerical tests to determine the adequacy of this specification to prevent the occurrence of seismic pounding between steel frame structures under near-field and far-field earthquakes. The results indicated that the recommended minimum separation gap based on the Australian Standard is inaccurate if low-rise structure in a coupled case is utilised under both near and far field earthquakes. The standard is adequate if a tall building is involved but only when a far-field earthquake happens. The research likewise presents results derived by using the ABS and SRSS methods.