• Steel and Composite Structures
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• v.14 no.2
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• pp.155-171
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• 2013

This study analytically evaluated the seismic performance of wind-designed diagrid tall steel buildings in regions of moderate/low seismicity and strong winds. To this end, diagrid tall steel buildings with varying wind exposure and slenderness ratio (building height-to-width ratio) conditions were designed to satisfy the wind serviceability criteria specified in the Korean Building Code and the National Building Code of Canada. A series of seismic analyses were then performed for earthquakes having 43- and 2475- year return periods utilizing the design guidelines of tall buildings. The analyses demonstrated the good seismic performance of these wind-designed diagrid tall steel buildings, which arises because significant overstrength of the diagrid system occurs in the wind design procedure. Also, analysis showed that the elastic seismic design process of diagrid tall steel buildings might be accepted based on some wind exposures and slenderness ratios.

• International Journal of High-Rise Buildings
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• v.7 no.1
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• pp.1-16
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• 2018

The emergence of tall buildings in the late $19^{th}$ century was possible by using new materials and separating the role of structures and that of non-structural walls from the traditional load-bearing walls that acted as both. The role of structures is more important in tall buildings than in any other building type due to the "premium for height". Among the walls freed from their structural roles, façades are of conspicuous importance as building identifiers, significant definers of building aesthetics, and environmental mediators. This paper studies dynamic interrelationship between the evolution of tall building structural systems and façade design, beginning from the early tall buildings of skeletal structures with primitive curtainwalls to the recent supertall buildings of various tubular and outrigger structures with more advanced contemporary curtainwalls.

• International Journal of High-Rise Buildings
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• v.1 no.2
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• pp.131-148
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• 2012

This paper attempts to summarize recent debates on tall buildings. It first explains the driving forces of constructing tall buildings including population increase, rural-to-urban migration, demographic change, agglomeration, and human aspiration. Next, it discusses disadvantages and challenging factors that are frequently raised in making a case against tall buildings including economics, environmental factors, historic context, public safety, and psychological issues. The paper concludes by affirming that tall buildings will persist in the $21^{st}$ century due to strong commitment to urban sustainability and significant population increase worldwide.

• International Journal of High-Rise Buildings
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• v.10 no.1
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• pp.63-71
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• 2021

Since 2006, the number of completed high-rise buildings over 200 meters have increased rapidly. Although there were some short-term cyclical troughs, the overall trend has still been growing. No longer constrained by technological limits, the development of high-rise buildings now depends on cooperation and compromise between social, economic, and political factors. This article extracts statistical data from the Council on Tall Buildings and Urban Habitat (CTBUH) to focus on the completion of high-rise buildings of 200 meters and above over the past 20 years from 2000 to 2019. Similarities and differences in the number, distribution, and function of high-rise buildings are analyzed, The paper also compares the impact of different political and economic environments on the development trends of high-rise buildings in China, the United States and the UAE.

• International Journal of High-Rise Buildings
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• v.7 no.3
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• pp.197-214
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• 2018

Tall buildings which began from about 40 m tall office towers in the late $19^{th}$ century have evolved into mixed-use megatall towers over 800 m. It is expected that even mile-high towers will soon no longer be a dream. Structural systems have always been one of the most fundamental technologies for the dramatic developments of tall buildings. This paper presents structural systems employed for the world's tallest buildings of different periods since the emergence of supertall buildings in the early 1930s. Further, structural systems used for today's extremely tall buildings over 500 m, such as core-outrigger, braced mega-tube, mixed, and buttressed core systems, are reviewed and their performances are studied. Finally, this paper investigates the potential of superframed conjoined towers as a viable structural and architectural solution for mile-high and even taller towers in the future.

• International Journal of High-Rise Buildings
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• v.8 no.4
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• pp.235-253
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• 2019

This paper reviews shape optimization studies for tall and super-tall building design. Firstly, shape effects on aerodynamic and response characteristics are introduced and discussed. Effects of various configurations such as corner modifications, taper, setback, openings, and twists are examined. Comprehensive comparative studies on various configurations including polygon building models, and composite type building models such as corner-cut and taper, corner-cut and taper and helical, and so on, are also discussed under the conditions of the same height and volume. Aerodynamic characteristics are improved by increasing the twist angle of helical buildings and increasing the number of sides of polygon buildings, but a twist angle of $180^{\circ}$ and a number of sides of 5 (pentagon) seem to be enough. The majority of examined configurations show better aerodynamic characteristics than straight-square. In particular, composite type buildings and helical polygon buildings show significant improvement. Next, shape effects on pedestrian-level wind characteristics around tall and super-tall buildings are introduced and discussed. Corner modification buildings show significant reductions in speed-up areas. On the other hand, setback and tapered models with wider projected widths near the ground show adverse effects on pedestrian-level wind characteristics.

• International Journal of High-Rise Buildings
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• v.9 no.3
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• pp.245-253
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• 2020

With the ever-increasing height of timber buildings, the complexity of timber as a structural material gives rise to behaviors not previously studied by engineers. An urgent call is needed regarding their performance in damage scenarios: activating alternative load paths in tall timber buildings is not the same as in tall buildings made with steel and concrete. In this paper we propose a robustness framework covering all building materials, whose application in timber may lead to new conceptual designs for the next generation of tall timber buildings. Qualitatively, the importance of building scale and the distinction between localized and systematic exposures are discussed, and how existing supertall structures can be an example for future generations of tall timber buildings. Quantitatively, the robustness index is introduced alongside a method to calculate the performance of a given building regarding robustness, in order to find the most cost-effective structural solutions for improved robustness. A three-level application recommendation is made, depending on the importance of the building in question. Primarily, the paper highlights the importance of conceptual design to achieve structural robustness and encourages the practicing engineering community to use the proposed framework to quantitatively come up with the new generation of tall timber buildings.

• International Journal of High-Rise Buildings
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• v.8 no.1
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• pp.57-69
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• 2019

After decades of high-speed development, designing tall buildings as critical components of urban habitat, rather than simply standing aloof from their environments, has become an important concern in many Asian cities. Nevertheless, the lack of quantitative understanding cannot support efficient architectural design or urban renewal that targets better place-making. This study attempts to fill the gap by providing a typological approach for measuring the social impact of tall buildings' ground conditions: that is, public space, podiums, and interfaces. The central business districts (CBD) of three Asian cities, Shanghai, Hong Kong, and Singapore, were selected as cases. Typical patterns and categories of lower-level public spaces among the three CBDs were abstracted via typological analyses and field study. The following evaluation is achieved through the analytic hierarchy process (AHP). This quantified approach helps to provide a visualization of high or low positive social impacts of tall buildings' lower-level public spaces among the three cases. This study also helps to suggest a design code for tall buildings aimed at a more human-oriented urban habitat.

• International Journal of High-Rise Buildings
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• v.6 no.3
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• pp.271-277
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• 2017

Safety, livability, and efficiency are the three prominent problems of tall buildings, which are also the severe challenges to designers. We proposed the idea of building the sky town to solve these problems, which can be summarized in two sentences, one is tall building multi-storised, and another one is vertical facilities municipal-infrastructurised. The tall building can be horizontally cut into several multi-storey buildings by some large platforms. The platform extends a certain width to block the fire from spreading. Tall buildings are connected together as a group. One of them is a traffic core, which is used for vertical transportation and MEP. It connects to traffic center such as metro, while most of the other tall buildings' cores can be very much released, so as to achieve maximum efficiency of floor usable area and to give good traffic organization. By combining traffic core, platforms, and multi-storey buildings' inner traffic, a transportation network is formed. Finally, we refer to the design of Raffles City Chongqing to make a sketch of sky town.

• International Journal of High-Rise Buildings
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• v.2 no.2
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• pp.153-169
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• 2013

The past decade has witnessed an unprecedented boom in tall and supertall building construction worldwide (Wood, 2011). Because of their massive bulk and soaring height, tall buildings often create serious placemaking problems. Employing extensive photographs and sketches, this paper examines architectural and urban design strategies that improve placemaking with tall buildings. The paper embraces a comprehensive approach that considers the relationship of tall buildings to their surroundings at the macro and micro scales. It also considers non-physical factors that tall buildings need to address, such as the social life the building creates. It is hoped that the placemaking factors discussed in this article will provide the required groundwork for future research that explores regulations and codes that foster placemaking with tall buildings.