• 국제초고층학회논문집
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• 제1권2호
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• pp.81-85
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• 2012

Vertical meteorological conditions encountered by super tall buildings, such as wind speed, temperature and humidity, vary due to their height. Therefore, it is necessary to consider these environmental changes to properly estimate the heating and cooling loads, and to minimize the energy demands for HVAC in super tall buildings. This paper aims to analyze how vertical meteorological changes affect heating and cooling loads of super tall buildings by using numerical simulation. A radiosonde, which observes atmospheric parameters of upper air such as wind speed, wind direction, temperature, relative humidity and pressure, was used to provide weather data for the building load simulation. A hypothetical super tall building was used for the simulation to provide quantified characteristics of the heating and cooling loads, comparing the lower, middle and upper parts of the building. The effect of weather data on the heating and cooling loads in super tall building was also discussed.

• 국제초고층학회논문집
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• 제12권4호
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• pp.307-320
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• 2023

Tall buildings are built with an abundant amount of materials, including structural materials, coming from our limited natural resources. Tall buildings that began from about 10-story tall office towers have evolved to over 150-story tall mixed-use megastructures. As a building becomes taller, structural material requirement to resist lateral wind loads becomes exponentially larger. Therefore, it is crucial to employ efficient structural systems and optimize their design, which will contribute to sustainable vertical built environments through preservation of resources. Tube type structures with large perimeter diagonals are among the most efficient structural systems for tall buildings. Developments of braced tube, braced megatube, diagrid structures, and their optimal design strategies are reviewed. Superframed conjoined towers, produced by interconnecting multiple clustered braced tubes, are presented as a new design direction to achieve not only structural but also architectural and social sustainable design goals.

• 국제초고층학회논문집
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• 제5권2호
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• pp.117-125
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• 2016

In this paper we discuss the terms "exo-spatial design," "solar carving," and "bridging" as strategies for creating more socially connective tall buildings. As a typology, high-rise residential buildings have a unique set of challenges to becoming fully activated urban participants in the cities in which they are located. While there is a general recognition and appreciation that tall buildings provide identity to a city, there is often criticism of how they relate to their surroundings. Critics have posited that tall buildings are insular and foreboding by their very nature. This paper explores several design avenues for architects to consider in order to improve the social aspect of tall buildings. As all cities become taller and denser to accommodate growth, the need to design social space in, on, and around tall buildings must be continually examined if we are to have cohesive urban fabric that supports communities.

• 국제초고층학회논문집
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• 제10권3호
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• pp.179-191
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• 2021

Tall buildings have generally been developed as solo towers. With the increase of the heights of tall buildings from about 10-story buildings to supertall and megatall buildings, their structural systems have evolved from interior structures to exterior structures and combined/mixed systems. This paper reviews structural systems developed for solo supertall and megatall buildings and discusses the challenges they face in terms of structural performance and architectural design as the building heights are ever increased. As a viable and more sustainable design alternative to extremely tall solo towers, superframed conjoined towers are presented. Their structural performances are investigated in comparison with solo tower structures. Further, architectural potentials of superframed conjoined towers are explored through design studies.

• Architectural research
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• 제21권4호
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• pp.91-98
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• 2019

In modern times, numerous cities are competing to create the unique skyline adjacent to the water. Tall buildings located across the river have a great contribution to the skyline of a riverfront city and can be a precious asset for the city. Moreover, in several cities, tall buildings and their impact on the urban skyline are a matter that should be considered and regulated in urban design. Therefore, as a prominent element in a larger visual setting of the city, tall buildings should improve the visual quality of the skyline rather than diminish that quality. This research attempts to provide an objective method to analyze the visual quality of the skyline made by a group of tall buildings through their feature of heights and spatial arrangement from riverfront views. The analysis is determined by the design variables of building heights variation, heights transition, density, and spacing of a group of tall buildings. A comparative case study of tall buildings in Yeouido and Lujiazui was conducted to prove the effectiveness of the analysis. The proposed method can be used in a simple way in the quantitative approach to quantify the visual quality of the skyline. In conclusion, Yeuido's skyline is not quite interesting from the riverfront view in terms of height variation and continuity of the skyline view because they are dispersed. Conversely, Lujiazui's skyline from the riverfront vantage points has a good quality in all aspects of the feature of height and spatial arrangements of tall buildings cluster. These factors can be used for the urban designer on how proposed tall buildings within the cluster should appropriately respond to adding image on the skyline.

• Wind and Structures
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• 제23권5호
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• pp.385-403
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• 2016

The across-wind dynamic loads on L-shaped tall buildings with various geometric dimensions were investigated through a series of wind tunnel testing. The lift coefficients, power spectral densities and vertical correlation coefficients of the across-wind loads were analyzed and discussed in details. Taking the side ratio and terrain category as key variables, empirical formulas for estimating the across-wind dynamic loads on L-shaped tall buildings were proposed on the basis of the wind tunnel testing results. Comparisons between the predictions by the empirical formulas and the wind tunnel test results were made to verify the accuracy and applicability of the proposed formulas. Moreover, a simplified procedure to evaluate the across-wind dynamic loads on L-shaped tall buildings was derived from the proposed formulas. This study aims to provide a simple and reliable way for the estimation of across-wind dynamic loads on L-shaped tall buildings.

• 국제초고층학회논문집
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• 제12권2호
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• pp.153-162
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• 2023

Achieving sustainable spaces is one of the emerging trends of tall buildings regarding their significant impacts on the cities. Reducing energy consumption and material using is investigated as a widely used approach to achieve more efficient tall buildings. Defining more efficient geometries and form modifications have been adopted for this goal. In this paper the effect of plan shape and diagrid angle on structural efficiency of diagrid tall buildings have been studied. A parametric workbench is applied to generate and analyze models. The goal is to find effective form parameters resulting in more efficient forms. Respectively, all models were generated in Rhino/grasshopper architecturally and analyzed by a finite element plug-in structurally. Based on the results, steeper angles almost cause more displacements and needs to be more stiffened. it can be seen almost more sided models need less weight for the structures and it could lead to more efficient forms.

• Wind and Structures
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• 제18권4호
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• pp.443-456
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• 2014

A popular modern architectural form for tall buildings is two (or more) towers which are structurally linked through such features as a shared podium or sky-bridges. The fundamental features of the wind loading and the structural links of such buildings can be studied by measuring load components on the individual unlinked towers along with their correlations. This paper describes application of dual high frequency force balance (DHFFB) in a wind tunnel study of the base wind loading exerted on generic tall twin buildings in close proximity. Light models of two identical generic tall buildings of square plan were mounted on DHFFB and the base wind loading exerted on the buildings was simultaneously acquired. The effects of the relative positions of the buildings on the correlations and coherences involving loading components on each building and on the two buildings were investigated. For some relative positions, the effects of the building proximity on the wind loading were significant and the loading was markedly different from that exerted on single buildings. In addition, the correlations between the loadings on the two buildings were high. These effects have potential to significantly impact, for example, the modally-coupled resonant responses of the buildings to the aerodynamic excitations. The presented results were not meant to be recommended for direct application in wind resistant design of tall twin buildings. They were intended to show that wind loading on tall buildings in close proximity is significantly different from that on single buildings and that it can be conveniently mapped using DHFFB.

• 국제초고층학회논문집
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• 제5권1호
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• pp.21-30
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• 2016

The structural efficiency of tall buildings heavily depends on the lateral stiffness and resistance capacity. Among those structural systems for tall buildings, outrigger system is one of the most common and efficient systems especially for those with relatively regular floor plan. The use of outriggers in building structures can be traced back from early 50 from the concept of deep beams. With the rise of building height, deep beams become concrete walls or now in a form of at least one story high steel truss type of outriggers. Because of the widened choice in material to be adopted in outriggers, the form and even the objective of using outrigger system is also changing. In the past, outrigger systems is only used to provide additional stiffness to reduce drift and deflection. New applications for outrigger systems now move to provide additional damping to reduce wind load and acceleration, and also could be used as structural fuse to protect the building under a severe earthquake condition. Besides analysis and member design, construction issue of outrigger systems is somehow cannot be separated. Axial shortening effect between core and perimeter structure is unavoidable. This paper presents a state-of-the-art review on the outrigger system in tall buildings including development history and applications of outrigger systems in tall buildings. The concept of outrigger system, optimum topology, and design and construction consideration will also be discussed and presented.

• 국제초고층학회논문집
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• 제5권4호
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• pp.319-326
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• 2016

The ingenuity of structural engineers in the field of tall and super-tall buildings has led to some of the most remarkable inventions. During this evolution of structural engineering concepts in the last 100 years, the technical challenges that engineers encountered were extraordinary and the advances were unprecedented. However, as the accomplishments of structural engineers are progressing, the desire for taller and safer structures is also increasing. The diagrid structural system is part of this evolving process as it develops a new paradigm for tall building design combining engineering efficiency and new architectural expression. The first appearances of this type of tall buildings have already been constructed and the interest of both engineering and architectural communities is growing mainly due to the many advantages compared to other structural systems. This paper presents a simple approach on optimizing member sizes for the diagonals of steel diagrid tall buildings. The optimizing method is based on minimizing the volume of the diagonal elements of a diagrid structure. The constraints are coming from the stiffness-based design, limiting the tip deflection of the building to widely accepted regulative limits. In addition, the current paper attempts to open the discussion on the important topic of optimization and robustness for tall buildings and also studies the future of the diagrid structural system.