• Journal of Korean Association for Spatial Structures
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• v.18 no.2
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• pp.51-58
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• 2018

Recently, measuring instruments for SHM of structures had being developed. In general, the wireless transmission of sensor signals, compared to its wired counterpart, is preferable due to its absence of triboelectric noise and elimination of the requirement for cumbersome cable. However, the research on the tall buildings with relatively small vibration levels is insufficient. Therefore, in this paper, we used the wireless MEMS sensor and iPad to compare and analyze the vibration measurements of three tall buildings and two towers.

• Wind and Structures
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• v.18 no.1
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• pp.21-35
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• 2014

The latest developments in topology optimization are integrated with Computational Fluid Dynamics (CFD) for the conceptual design of building structures. The wind load on a building is simulated using CFD, and the structural response of the building is obtained from finite element analysis under the wind load obtained. Multiple wind directions are simulated within a single fluid domain by simply expanding the simulation domain. The bi-directional evolutionary structural optimization (BESO) algorithm with a scheme of material interpolation is extended for an automatic building topology optimization considering multiple wind loading cases. The proposed approach is demonstrated by a series of examples of optimum topology design of perimeter bracing systems of high-rise building structures.

• Wind and Structures
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• v.18 no.5
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• pp.567-598
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• 2014

In this paper, wind induced aerodynamic loads on a standard tall building have been evaluated through large-eddy simulation (LES) technique. The flow parameters of an open terrain were recorded from the downstream of an empty boundary layer wind tunnel (BLWT) and used to prescribe the transient inlet boundary of the LES simulations. Three different numerically generated inflow boundary conditions have been investigated to assess their suitability for LES. A high frequency pressure integration (HFPI) approach has been employed to obtain the wind load. A total of 280 pressure monitoring points have been systematically distributed on the surfaces of the LES model building. Similar BLWT experiments were also done to validate the numerical results. In addition, the effects of adjacent buildings were studied. Among the three wind field generation methods (synthetic, Simirnov's, and Lund's recycling method), LES with perturbation from the synthetic random flow approach showed better agreement with the BLWT data. In general, LES predicted peak wind loads comparable with the BLWT data, with a maximum difference of 15% and an average difference of 5%, for an isolated building case and however higher estimation errors were observed for cases where adjacent buildings were placed in the vicinity of the study building.

• Wind and Structures
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• v.14 no.6
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• pp.499-515
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• 2011

Low-frequency building vibration is known to induce symptoms of motion sickness in some occupants. This paper examines how the adoption of a theory of motion sickness, in conjunction with a dose-response model might inform the real-world problem of managing and designing standards for tall building motion sway. Building designers require an understanding of human responses to low-dosage motion that is not adequately considered by research into motion sickness. The traditional framework of Sensory Conflict Theory is contrasted with Postural Instability Theory. The most severe responses to motion (i.e., vomiting) are not experienced by occupants of wind-excited buildings. It is predicted that typical response sets to low-dosage motion (sleepiness and fatigue), which has not previously been measured in occupants of tall-buildings, are experienced by building occupants. These low-dose symptoms may either be masked from observation by the activity of occupants or misattributed to the demands of a typical working day. An investigation of the real-world relationship between building motion and the observation of low-dose motion sickness symptoms and a degradation of workplace performance would quantify these effects and reveal whether a greater focus on designing for occupant comfort is needed.

• International Journal of High-Rise Buildings
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• v.3 no.1
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• pp.1-8
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• 2014

When seismic isolation system is applied to high aspect-ratio (height/wide-ratio) steel structures, there are several problems to be taken into consideration. One is lifting up tensile force on the isolation bearing by overturning moment caused by earthquake. Another is securing building stiffness to produce seismic isolation effects. Under these conditions, this paper reports the structural design of high-rise research building in the campus of Tokyo Institute of Technology. With the stepping-up system for the corner bearings, the narrow sides of single span framework are designed to concentrate the dead load as counter-weight for the tensile reaction under earthquake. Also we adopted concrete in-filled steel column and Mega-Bracing system covering four layers on north & south framework to secure the horizontal stiffness of the building.

• International Journal of High-Rise Buildings
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• v.6 no.1
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• pp.83-89
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• 2017

Due to the time-dependent properties of materials, structures, and loads, accurate time-dependent effects analysis and precise construction controls are very significant for rational analysis and design and saving project cost. Elevation control is an important part of the time-dependent construction control in supertall structures. Since supertall structures have numerous floors, heavy loads, long construction times, demanding processes, and are typically located in the soft coastal soil areas, both the time-dependent features of superstructure and settlement are very obvious. By using the time-dependent coupling effect analysis method, this paper compares Shanghai Tower's vertical deformation calculation and elevation control scheme, considering foundation differential settlement. The results show that the foundation differential settlement cannot be ignored in vertical deformation calculations and elevation control for supertall structures. The impact of foundation differential settlement for elevation compensation and pre-adjustment length can be divided into direct and indirect effects. Meanwhile, in the engineering practice of elevation control for supertall structures, it is recommended to adopt the multi-level elevation control method with relative elevation control and design elevation control, without considering the overall settlement in the construction process.

• Structural Engineering and Mechanics
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• v.85 no.3
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• pp.381-391
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• 2023

The seismic performance of the tall building equipped with a tuned mass damper (TMD) considering soil-structure interaction (SSI) effects is well studied in the literature. However, these studies are performed on the nominal model of the seismic-excited structural system with SSI. Hence, the outcomes of the studies may not valid for the actual structural system. To address the study gap, the reliability theory as a useful and powerful method is utilized in the paper. The present study aims to carry out reliability analyses on tall buildings equipped with TMD under near-field pulse-like (NFPL) ground motions considering SSI effects using a subset simulation (SS) method. In the presence of uncertainties of the structural model, TMD device, foundation, soil, and near-field pulse-like ground motions, the numerical studies are performed on a benchmark 40-story building and the failure probabilities of the structures with and without TMD are evaluated. Three types of soils (dense, medium, and soft soils), different earthquake magnitudes (M_w = 7,0. 7,25. 7,5 ), different nearest fault distances (r = 5. 10 and 15 km), and three seismic performance levels of immediate occupancy (IO), life safety (LS), and collapse prevention (CP) are considered in this study. The results show that tall buildings built near faults and on soft soils are more affected by uncertainties of the structural and ground motion models. Hence, ignoring these uncertainties may result in an inaccurate estimation of the maximum seismic responses. Also, it is found the TMD is not able to reduce the failure probabilities of the structure in the IO seismic performance level, especially for high earthquake magnitudes and structures built near the fault. However, TMD is significantly effective in the reduction of failure probability for the LS and CP performance levels. For weak earthquakes and long fault distances, the failure probabilities of both structures with and without TMD are near zero, and the efficiency of the TMD in the reduction of failure probabilities is reduced by increasing earthquake magnitudes and the reduction of fault distance. As soil softness increases, the failure probability of structures both with and without TMD often increases, especially for severe near-fault earthquake motion.

• Journal of Korean Association for Spatial Structures
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• v.11 no.4
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• pp.79-88
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• 2011

Recently, complex-shaped tall buildings represented by 3T(Twisted, Tapered, Tilted) are planed largely. A diagrid structural system is one of the most widely used structural system for complex-shaped tall buildings because of its structural efficiency and formativeness. Plans for tilted tall buildings are largely presented because of beauty of a sculpture and many of buildings use diagrid structural systems. Lateral displacements of tilted tall buildings are induced by not only lateral loads but also self weight. Therefore, reduction of lateral responses of tilted tall buildings is as important as typical tall buildings. In this study, a smart TMD is introduced to reduce seismic responses of tilted diagrid tall buildings and its control performance is evaluated. MR damper is employed for the smart TMD and ground-hook controller is used as a control algorithm for the smart TMD. 100-story tall building is used as an example structure. Control performances of uncontrolled case, controlled case with TMD and controlled case with smart TMD are compared and investigated. Numerical simulation has shown that smart TMD presented good control performance for displacement response but acceleration response was not controlled well.

• International Journal of High-Rise Buildings
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• v.13 no.1
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• pp.33-56
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• 2024

This paper examines China's rapid shift from low-rise to high-rise urban development, focusing on Shanghai as a case study. It provides a detailed analysis of the rapid vertical developments over the past five decades, highlighting gradual and sudden tall building changes. The study also surveys tall building development in the ten "tallest cities" across China, including Hong Kong, Shenzhen, Guangzhou, Shanghai, Wuhan, Chongqing, Chengdu, Shenyang, Hangzhou, and Nanning, while listing the tallest ten buildings in each city. The focus is on the drivers behind these towering structures: globalization, an economic powerhouse, and finance center, urbanization and population density, architectural innovation and ambition, competition and prestige, land availability and utilization, government support and planning, and tourism. The paper critically examines the sustainability of this trend in light of new Chinese policies restricting the construction of high-rise buildings exceeding 500m and 250m in smaller cities due to safety and security concerns. This prompts a reflection on the long-term viability and implications of the predominantly high-rise trajectory in urban development.

• International Journal of High-Rise Buildings
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• v.5 no.3
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• pp.221-232
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• 2016

With the booming of construction and property industries in China, the demand for high-rises and mega-scale buildings with more integrated building functions, open- and tailor-shaped outlooks, better connections to municipal infrastructures, and higher grades of building importance has been increasing in the past two decades. The seismic design and engineering of such modern mega-buildings face engineering challenges such as hazard mitigation of extreme actions and surroundings, integrated structural frameworks and building skins, complex connections, and overall construction efficiency. It is the work of a new generation of civil and structural engineers to enhance engineering efficiency and achieve overall engineering, environmental, and economical effectiveness for these high-rise projects. This paper elaborates the above topics through case studies on the design and construction of four such developments in China. Some rethinking is conducted on evolution in modern seismic engineering and design through innovation to achieve an acceptable level of overall sustainability and building effectiveness.