• Title, Summary, Keyword: tall buildings

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Stack Effect Guidelines for Tall, Mega Tall and Super Tall Buildings

  • Simmonds, Peter;Zhu, Rui
    • International Journal of High-Rise Buildings
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    • v.2 no.4
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    • pp.323-330
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    • 2013
  • The ASHRAE Technical Committee for Tall Buildings, TC 9.12, has defined a tall building as one whose height is greater than 300 feet (91m). Since the publication of the HVAC Design Guide for Tall Commercial Buildings in 2004, there were only about 300 buildings taller than 200 meters; this number has risen to 600 in 2010 and the prediction 765 buildings taller than 200 meters in 2012. There has also been an introduction of two new classes of tall buildings: ${\bullet}$ Mega tall, which are buildings taller than 300 m, and ${\bullet}$ Super tall, which are buildings taller than 600 m. The effect of ambient air temperature over the height of buildings, especially Mega tall and Super tall buildings. The ambient climatic conditions vary with altitude and these changes in ambient conditions can seriously affect load calculations and performance of super and mega tall buildings. This paper presents revised calculations for stack effect for Tall, Mega Tall and Super tall Buildings.

Sustainability Impact of Tall Buildings: Thinking Outside the Box!

  • Aminmansour, Abbas
    • International Journal of High-Rise Buildings
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    • v.8 no.2
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    • pp.155-160
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    • 2019
  • Applying the criteria regularly used in sustainability assessment of "ordinary" buildings leads to the observation that tall buildings are "not sustainable." But nothing is ordinary about tall buildings and such an evaluation is not appropriate. While tall buildings may not measure up to the same sustainability standards applied to not-tall buildings, they do indeed have a significant sustainability impact if assessed within their appropriate context. This paper promotes the idea that in evaluating "sustainability" of tall buildings, we must look at their sustainability impact beyond their physical boundaries and within the urban context.

Diagrid Systems for Structural Design of Complex-Shaped Tall Buildings

  • Moon, Kyoung Sun
    • International Journal of High-Rise Buildings
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    • v.5 no.4
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    • pp.243-250
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    • 2016
  • Today's architectural design trend based on the recognition of pluralism has led to multiple design directions for all building types including tall buildings. This contemporary design trend has produced many complex-shaped tall buildings, such as twisted, tilted, tapered and freeform towers. Among many different structural systems developed for tall buildings, the diagrid system, with its powerful structural rationale and distinguished aesthetic potential, is one of the most widely used systems for today's tall buildings. This paper studies structural performance of diagrid systems employed for complex-shaped tall buildings. Twisted, tilted, tapered and freeform tall buildings are designed with diagrid structures, and their structural performances are investigated. For the twisted diagrid study, the buildings are twisted up to 3 degrees per floor. In the tilted diagrid study, the angles of tilting range from 0 to 13 degrees. The impact of eccentricity is investigated for gravity as well as lateral loads in tilted towers. In the study of tapered diagrid structures, the angles of tapering range from 0 to 3 degrees. In the study of freeform diagrid structures, lateral stiffness of freeform diagrids is evaluated depending on the degree of fluctuation of free form. The freeform floor plans fluctuate from plus/minus 1.5 meter to plus/minus 4.5 meter boundaries of the original square floor plan. Parametric structural models are generated using appropriate computer programs and the models are exported to structural engineering software for design, analyses and comparative studies.

Low-energy Tall Buildings? Room for Improvement as Demonstrated by New York City Energy Benchmarking Data

  • Leung, Luke;Ray, Stephen D.
    • International Journal of High-Rise Buildings
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    • v.2 no.4
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    • pp.285-291
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    • 2013
  • This paper proposes a framework for understanding the energy consumption differences between tall and low-rise buildings. Energy usage data from 706 office buildings in New York illustrates expected correlations from the framework. Notable correlations include: taller buildings tend to use more energy until a plateau at 30~39 floors; tall buildings in Manhattan use 20% more energy than low-rise buildings in Manhattan, while tall buildings outside Manhattan use 4% more energy than low-rise buildings outside Manhattan. Additional correlations are discussed, among which is the trend that the Energy Star program in New York City assigns higher ratings to tall buildings with higher EUIs than low-rise buildings with the same EUI. Since Energy Star is based on regressions of existing buildings, the Energy Star ratings suggest taller buildings have higher EUIs than shorter buildings, which is confirmed by the New York City energy benchmarking data.

Outrigger Systems for Structural Design of Complex-Shaped Tall Buildings

  • Moon, Kyoung Sun
    • International Journal of High-Rise Buildings
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    • v.5 no.1
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    • pp.13-20
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    • 2016
  • Today's architecture can be best understood only through the recognition of pluralism, and, as is true of other building types, multiple design directions are prevalent for tall buildings. This contemporary design trend has produced many complex-shaped tall buildings, such as twisted, tilted and tapered form towers. Among many different structural systems developed for tall buildings, the outrigger system, with its inherent structural efficiency and flexibility in façade design, is widely used for contemporary tall buildings. This paper studies structural performance of outrigger systems employed for complex-shaped tall buildings. Twisted, tilted and tapered tall buildings are designed with outrigger structures, and their structural performance is investigated. For the twisted outrigger study, the buildings are twisted up to 3 degrees per floor. In the tilted outrigger study, the angles of tilting range from 0 to 13 degrees. The impact of eccentricity is investigated for gravity as well as lateral loads in tilted towers. In the study of tapered outrigger structures, the angles of tapering range from 0 to 3 degrees. Parametric structural models are generated using appropriate computer programs for these studies, and the models are exported to structural engineering software for design and analyses.

Why Tall Buildings? The Potential of Sustainable Technologies in Tall Buildings

  • Elbakheit, Abdel Rahman
    • International Journal of High-Rise Buildings
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    • v.1 no.2
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    • pp.117-123
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    • 2012
  • This paper discusses major strengths of tall buildings that distinguish them as sustainable solutions for the built environment. It sheds light on some of the key attributes of tall buildings as well as materials and technologies that could boost their performance environmentally, economically and technically as well as the natural habitats containing them. Tall buildings are portrait as major successful options for accommodating the ever increasing urban world population, with little negative impact on ecologies and environmental habitats worldwide. The role of tall buildings as 'vertical garden sub-cities' mitigating modern city problems of 'urban heat islands' and sprawling cities is explored. A few building examples as well as city developments are presented which represent the new generation of sustainable tall buildings that are setting trends for future projects incorporating innovations in materials and building systems and designs.

Comparative Evaluation of Structural Systems for Tilted Tall Buildings

  • Moon, Kyoung Sun
    • International Journal of High-Rise Buildings
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    • v.3 no.2
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    • pp.89-98
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    • 2014
  • Employing tilted forms in tall buildings is a relatively new architectural phenomenon, as are the cases with the Gate of Europe Towers in Madrid and the Veer Towers in Las Vegas. This paper studies structural system design options for tilted tall buildings and their performances. Tilted tall buildings are designed with various structural systems, such as braced tubes, diagrids and outrigger systems, and their structural performances are studied. Structural design of today's tall buildings built with higher strength materials is generally governed by lateral stiffness. Tilted towers are deformed laterally not only by lateral loads but also by dead and live loads due to their eccentricity. The impact of tilting tall buildings on the gravity and lateral load resisting systems is studied. Comparative evaluation of structural systems for tilted tall buildings is presented.

Wind tunnel investigation of correlation and coherence of wind loading on generic tall twin buildings in close proximity

  • Lim, Juntack;Bienkiewicz, Bogusz
    • Wind and Structures
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    • v.18 no.4
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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.

Conjoined Tower Structures for Mile-High Tall Buildings

  • Moon, Kyoung Sun
    • International Journal of High-Rise Buildings
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    • v.8 no.1
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    • pp.29-36
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    • 2019
  • Tall buildings are one of the most viable solutions to deal with the global phenomenon of rapid population increase and urbanization. While tall buildings are an essential building type to accommodate ever-growing urban population, as buildings become very tall they also produce many critical design challenges related to social interactions, emergency egress, structural systems, etc. While many different design solutions can be sought to resolve these challenging issues of tall buildings, this paper investigates potential of conjoined towers in producing more livable and sustainable megatall building complexes with an emphasis on their capability in efficiently providing exceedingly tall building structures.

Shielding effects on a tall building from a row of low and medium rise buildings

  • Zu, G.B.;Lam, K.M.
    • Wind and Structures
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    • v.27 no.6
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    • pp.439-449
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    • 2018
  • Wind loading of a tall building built amidst a group of buildings in urban environment is always greatly affected by shielding effects. Wind tunnel tests were carried out to assess the shielding provided by a row of low-rise or medium-rise buildings upstream a square-section tall building of height-to-breadth ratio 6. Mean and dynamic wind loads on the tall building were measured at different wind incidence angles and presented as interference factors (IFs). It is found that presence of a row of upstream buildings provides significant shielding to the tall building. At normal wind incidence, the mean along-wind loads and all components of fluctuating wind loads on the tall building are always reduced by shielding. Vortex shedding seems to still occur on the upper exposed part of the tall building but the vortex excitation levels are largely reduced. The degree of shielding is found to depend on a number of arrangement parameters of the row of upstream buildings. Empirical equations are proposed to quantify the shielding effect based on the wind tunnel data.