• International Journal of High-Rise Buildings
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• v.9 no.3
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• pp.213-220
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• 2020

This paper reflects on the structural design of Haut; a 21-storey high-end residential development in Amsterdam, the Netherlands. Construction started in 2019 and is in progress at the time of writing. Upon completion in 2021, Haut will be the first residential building in the Netherlands to achieve a 'BREEAM-outstanding' classification. The building will reach a height of 73 m, making it the highest timber structure in the Netherlands. It contains some 14.500 ㎡ of predominantly residential functions. It features a hybrid concrete-timber stability system and concrete-timber floor panels. This paper describes the concepts behind the structural design for Haut and will touch upon the main challenges that have arisen from the specific combination of characteristics of the project. The paper describes the design of the stability system and -floor system, the analysis of differential movements between concrete and timber structures and wind vibrations. The paper aims to show how the design team has met these specific challenges by implementing a holistic design approach and integrating market knowledge at an early stage of the design.

• International Journal of High-Rise Buildings
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• v.10 no.1
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• pp.55-62
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• 2021

The paper reports the result of a 2-year long research conducted by CTBUH on the design possibilities enabled by the Ropeless and Multidirectional elevator systems, investigating how such a significant innovation (or better to say revolution) in the vertical transportation could affect tall buildings first and cities then. The purpose of the study is to prefigure the adoption of ropeless and multidirectional cabins for tall buildings mobility, with the aim to overcome the evolutionary bottleneck of the high-rise building type due to the exclusively vertical direction of transport, which limited, over the years, the design possibilities in terms of height, shape and relations with the surrounding environment. CTBUH research team, together with professionals in the field and supporting academic advisors, developed a series of design considerations on plan organizations, dispatching alternatives and on the integration of horizontal direction in the circulation, with the aim of anticipating potential and criticality arising from the application of ropeless and multidirectional systems.

• International Journal of High-Rise Buildings
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• v.12 no.1
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• pp.1-9
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• 2023

The last 30 years have seen a rapid growth in the number of supertall buildings across the world, with newly completed buildings continuing to rank among the tallest 100 every year. Chinese projects notably play a pivotal role in these constant updates. It is caused by the interweaving of population and urbanization, economic considerations, and further, a series of accompanying urban problems. This paper focuses on the world's 100 tallest buildings in the last 30 years, and compares this collection of projects across five years via the dimensions of height, distribution, function and structural material. The intention is to discuss and interpret the influence factors and developing trends, some of which have been apparent over a dozen years, while others are just beginning to take shape, thus to provide an opportunity to preview the types of supertall buildings in the future.

• International Journal of High-Rise Buildings
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• v.11 no.1
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• pp.61-68
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• 2022

The Address Jumeirah Resort is a mixed-use 77-story tower reaching a height of 301 meters with a slenderness ratio of 13.5:1. The development is situated in the Jumeirah Beach District and accommodates 217 key five-star hotel suites, 478 residential apartments, 444 serviced-branded apartments, retail shops, ballrooms and entertainment facilities around the premises. The building has over 242,000 m2 of usable area. The project is an award-winning development that broke multiple Guinness records. The focus of the paper is to present the challenges faced in the structural design and construction of the super tall tower and the highest occupiable skybridge in the world.

• Journal of architectural history
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• v.9 no.3 s.24
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• pp.51-69
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• 2000

This study tries to analyze the development of architectural technologies appeared in several tall buildings and large spatial structures from 1955 to 1999 in Korea. We suppose that these buildings represent the development of technology in Korean modern architecture. By the detailed analysis of these buildings, we can arrive at a conclusion as such; During the years 1955-1999, there existed a great changement in the eighties. We can find this fact very well in the domain of structural system and curtain wall system. In large spatial structures, the structural-system of shell and steel truss dome was replaced by that of space frame, space truss and cable truss with membrane. In tall building, the structural system of rigid frame and shear wall was replaced by tubular system, core and outrigger system. Korean architects introduced the aluminum curtain wall in the sixties, but its low technological level caused many problems in reality. Therefore, precast concrete curtain wall appeared from seventies as the main method for an outer wall in tall building. With the augmentation of height after 1980, PC curtain wall was replaced by the aluminum curtain wall of unit type and structural glass wall system. These systems help to stress the transparency in a tall building.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.4
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• pp.247-254
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• 2003

A study was carried to compare two varieties of tall fescue(Festuca arundinacea Schr.): Fawn (endophyte infection) and Roa(endophyte-free). The study examined plant height, botanical composition, and dry matter yield of mixed pasture. The cattle grazed on a mixed pasture of tall fescue species and orchardgrass(Dactylis glomerata L.), perennial ryegrass(Lolium perenne L.) and white clover(Trifolium repens L.) during March 22, 1997, to September 21, 1997. The number of grazing animals was 4.3/ paddock(50m x50m) and was adjusted according to the condition of pasture. Dry matter yields determined on ungrazed pasture(7-time harvests) were 1,690 $\pm$407kg and 1,128 $\pm$ 238kg/ha on pastures consisting of Fawn and Roa, respectively. This difference was significant(P<0.01). There were 17.71 $\pm$ 1.27cm and 12.83$\pm$0.90cm in average plant lengths of Fawn and Roa(P<0.01), respectively The botanical composition of tall fescue and orchardgrass in the mixture treatment included in the Fawn variety were shown in 34.2 and 3.8％, comparing Roa with 17.1 and 9.6％, on the 21th of September, 1997, respectively. Tall fescue Roa represented a higher botanical composition than orchardgrass(a main species on Cheju). Crude protein content of Fawn was slightly less than that of Roa. From these results, we may conclude that Roa variety is nutritionally better, but is less adaptible to high temperature climate than Fawn. However, Roa variety is still better than orchardgrass in high temperature conditions.

• Steel and Composite Structures
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• v.34 no.3
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• pp.393-407
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• 2020

The braced tube frame system, a combination of perimeter frame and bracing frame, is one of the systems used in tall buildings. Due to the implementation of this system in tall buildings and the high rigidity resulting from the use of general bracing, providing proper ductility while maintaining the strength of the structure when exposing to lateral forces is essential. Also, the high stress at the connection of the beam to the column may cause a sudden failure in the region before reaching the required ductility. The use of Reduced Beam Section connection (RBS connection) by focusing stress in a region away from beam to column connection is a suitable solution to the problem. Because of the fact that RBS connections are usually used in moment frames and not tested in tall buildings with braced tube frames, they should be investigated. Therefore, in this research, three tall buildings in height ranges of 20, 25 and 30 floors were modeled and designed by SAP2000 software, and then a frame in each building was modeled in PERFORM-3D software under two RBS-free system and RBS-based system. Nonlinear time history dynamic analysis is used for each frame under Manjil, Tabas and Northridge excitations. The results of the Comparison between RBS-free and RBS-based systems show that the RBS connections increased the absorbed energy level by reducing the stiffness and increasing the ductility in the beams and structural system. Also, by increasing the involvement of the beams in absorbing energy, the columns and braces absorb less energy.

• Structural Engineering and Mechanics
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• v.42 no.5
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• pp.715-728
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• 2012

This paper deals with determining the fundamental frequency of tall buildings that consist of framed tube, shear core, belt truss and outrigger systems in which the framed tube and shear core vary in size along the height of the structure. The effect of belt truss and outrigger system is modeled as a concentrated rotational linear spring at the belt truss and outrigger system location. Many cantilevered tall structures can be treated as cantilevered beams with variable cross-section in free vibration analysis. In this paper, the continuous approach, in which a tall building is replaced by an idealized cantilever continuum representing the structural characteristics, is employed and by using energy method and Hamilton's variational principle, the governing equation for free vibration of tall building with variable distributed mass and stiffness is obtained. The general solution of governing equation is obtained by making appropriate selection for mass and stiffness distribution functions. By applying the separation of variables method for time and space, the governing partial differential equation of motion is reduced to an ordinary differential equation with variable coefficients with the assumption that the transverse displacement is harmonic. A power-series solution representing the mode shape function of tall building is used. Applying boundary conditions yields the boundary value problem; the frequency equation is established and solved through a numerical process to determine the natural frequencies. Computer program has been developed in Matlab (R2009b, Version 7.9.0.529, Mathworks Inc., California, USA). A numerical example has been solved to demonstrate the reliability of this method. The results of the proposed mathematical model give a good understanding of the structure's dynamic characteristics; it is easy to use, yet reasonably accurate and suitable for quick evaluations during the preliminary design stages.

• Wind and Structures
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• v.34 no.5
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• pp.407-419
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• 2022

Many factors should be considered by architects and designers for designing a tall building. Wind load is one of these important factors that govern the design of tall building structures and can become a serious challenge when buildings tend to be built very tall and slender. On the other hand, through the initial stages of a design process, choosing the design geometry greatly affects the wind-induced forces on a tall building. With this respect, geometric shapes with 3-fold rotational symmetry are one of the applied plan shapes in tall buildings. This study, therefore, aims to investigate the aerodynamic characteristics of 8 different geometrical shapes using Computational Fluid Dynamics (CFD) by measuring the drag and lift forces. A case study approach was conducted in which different building shape models have the same total gross area and the same height of 300 meters. The simulation was an incompressible transient flow that ran 1700 timesteps (85 seconds on the real-time scale). The results show a great difference between wind-induced force performance of buildings with different plan shapes. Generally, it is stated that the shapes with the same area, but with smaller perimeters, are better choices for reducing the drag force on buildings. Applying the lift force, the results show that the buildings with plan shapes that have rounded corners act better in crosswind flow while, those with sharp corners induce larger forces in the same direction. This study delivers more analytical understanding of building shapes and their behavior against the wind force through the parametric modelling.

• Atmosphere
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• v.34 no.1
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• pp.69-81
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• 2024

In this paper, Annual flux variations in the Boseong Tall Tower (BTT) from 2016 to 2020 were analyzed using data from three levels (2.5 m, 60 m, and 300 m). BTT was installed in Boseong-gun, Jeollanam-do in February 2014 and continued to conduct energy exchange observations such as CO2, sensible heat, and latent heat using the eddy covariance method until March 2023. The BTT was located in a very flat and uniform paddy field, and flux observations were conducted at four levels: 2.5 m, 60 m, 140 m, and 300 m above ground. Surface energy balance was confirmed from observed data of net radiation flux, soil heat flux, sensible heat flux, and latent heat flux. Additionally, 2.5 m height surface fluxes, which are most influenced by agricultural land, were compared with data from Local Data Assimilation and Prediction System (LDAPS) of the Korea Meteorological Administration to evaluate the accuracy of LDAPS flux data. The correlation coefficient between LDAPS flux data and observed values was 0.95 or higher. Excluding summer latent heat flux data, there was a general tendency for LDAPS data to be higher than observed values. The footprint areas estimated below 60 m height mainly covered agricultural land, and flux observations at 2.5 m and 60 m heights showed typical agricultural characteristics. In contrast, the footprint estimated at 300 m height did not show agricultural characteristics, indicating that observations at this height encompassed a wide range, including mountains, sea, and roads. The analysis results of long-term flux observations can contribute to understanding the energy and carbon dioxide fluxes in agricultural fields. Furthermore, these results can be utilized as essential data for validating and improving numerical models related to such fluxes.