• International Journal of High-Rise Buildings
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• v.3 no.1
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• pp.49-64
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• 2014

Natural vibration period is an important parameter for high-rise building, Based on 414 high-rise buildings completed or passed over-limit approval in China, the distribution law of natural vibration periods is analyzied. In order to satisfy the design requirements, such as global stability, story drift limit and minimum shear-gravity ratio, the reference ranges of fundamental periods $T_1$ are $0.3{\sqrt{H}}{\sim}0.4{\sqrt{H}}$ when the structural heights $H{\geq}250m$, when 150 m ${\leq}$ H < 250m, $T_1=0.25{\sqrt{H}}{\sim}0.4{\sqrt{H}}$, when 100 m ${\leq}$ H < 150 m, $T_1=0.2{\sqrt{H}}{\sim}0.35{\sqrt{H}}$, when 50 m $ {\leq}$ H < 100m, $T_1=0.15{\sqrt{H}}{\sim}0.3{\sqrt{H}}$. These can provide reference data for controlling mass and rigidity of high-rise buildings.

• International Journal of High-Rise Buildings
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• v.3 no.1
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• pp.9-19
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• 2014

In this study the seismic performances of reinforced concrete apartment buildings with Y- and box-shaped plans having central core are investigated. Three types of model structures are designed for each shape depending on the amount of shear partition walls: structures with all shear walls, structures with all columns except the core walls, and structures with shear walls and columns combined. The required amount of concrete to satisfy the specified design loads is the largest in the all shear wall structures, and decreases as more and more shear walls are replaced with columns. The amount of re-bars increased significantly in the flat plate structures. According to nonlinear static and dynamic analysis results, the structures with all shear walls and all columns turn out to have the largest and the smallest strengths, respectively. However it is observed that even the all-column structures with shear core have proper load resisting capacity for design level seismic load.

• International Journal of High-Rise Buildings
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• v.3 no.3
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• pp.205-214
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• 2014

The super high rise building construction is characterized by a large quantity of engineering works and structural components, high demanding of construction technology and complex cross operations. As the height of super high rise building increases, the construction difficulties increase, it is challenging the steel structural building construction technology. In this paper, the key technologies in the construction of Chinese modern super high rise steel structure building have been studied. The innovative tower crane supporting frame suspension disassembly technology has been developed to allow the crane supporting frame to turnover in the air without occupying materials stockyard. A new self-elevating platform technique which is capable of striding over structural barriers has been developed. This new technology allows the platform to be self-elevated along variable cross section column with a maximum 600 mm size change. A new automatic submerged arc welding technology has also been developed to ensure the process continuity and quality stability of welding job on the construction site.

• International Journal of High-Rise Buildings
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• v.3 no.3
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• pp.215-221
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• 2014

Ultra-high strength concrete and high tensile steel are becoming very attractive materials for high-rise buildings because of the need to reduce member size and structural self-weight. However, limited test data and design guidelines are available to support the applications of high strength materials for building constructions. This paper presents significant findings from comprehensive experimental investigations on the behaviour of tubular columns in-filled with ultra-high strength concrete at ambient and elevated temperatures. A series of tests was conducted to investigate the basic mechanical properties of the high strength materials, and structural behaviour of stub columns under concentric compression, beams under moment and slender beam-columns under concentric and eccentric compression. High tensile steel with yield strength up to 780 MPa and ultra-high strength concrete with compressive cylinder strength up to 180 MPa were used to construct the test specimens. The test results were compared with the predictions using a modified Eurocode 4 approach. In addition, more than 2000 test data samples collected from literature on concrete filled steel tubes with normal and high strength materials were also analysed to formulate the design guide for implementation in practice.

• International Journal of High-Rise Buildings
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• v.3 no.3
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• pp.231-241
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• 2014

Ductile fracture is one of the most common failure modes of steel beam-to-column connections in moment resisting frames. Most proposed evaluation methods of the plastic deformation capacity of a beam until ductile fracture are based on steel beam tests, where the material's yield strength/ratio, the beam's moment gradient, and loading history are the most important parameters. It is impossible and unpractical to cover all these parameters in real tests. Therefore, a new attempt to evaluate a beam's plastic deformation capacity through analysis is introduced in this paper. Another important issue is about the loading histories. Recent years, the effect on the structural component under long-duration ground motion has drawn great attentions. Steel beams tends to experience a large number of loading cycles with small amplitudes during long-duration earthquakes. However, current research often focuses on the beam's behavior under standard incremental loading protocols recommended by respective countries. In this paper, the plastic deformation capacity of steel beams subjected to long duration ground motions was evaluated through analytical methodology.

• International Journal of High-Rise Buildings
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• v.3 no.1
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• pp.81-87
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• 2014

The use of Buckling Restrained Braces (BRB) for enhancing the performance of the buildings is gaining wider acceptance. This paper presents the first application of these devices in a major high-rise building in the Philippines. A 50-storey residential reinforced concrete building tower, with ductile core wall, with BRB system is investigated. The detailed modeling and design procedure of buckling restrained brace system is presented for the optimal design against the two distinct levels of earthquake ground motions; serviceable behavior for frequent earthquakes and very low probability of collapse under extremely rare earthquakes. The stiffness and strength of the buckling restrained brace system are adjusted to optimize the performance of the structural system under different levels of earthquakes. Response spectrum analysis is conducted for Design Basis Earthquake level and Service level, while nonlinear time history analysis is performed for the most credible earthquake. The case study results show the effectiveness of buckling restrained braces.

• International Journal of High-Rise Buildings
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• v.3 no.1
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• pp.73-79
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• 2014

In recent years, the performance requested for which an ultra-high rise buildings is diversified. Large spans are designed in order to gain wide workspace. Column positions are shifted in middle stories to provide space different from neighboring floors. Moreover, in the bottom layers of the building, it is becoming more important to expand freedom to plan flexibility such as creating publically opened wide atria that gives attractive free space. Earthquake-proof criteria is also changing not only human life protection deign but also a design that allows functional continuity. In order to achieve thee needs, as one of technology, we have developed ultra-high strength concrete filled tubular (CFT) columns of the box section that combine ultra-high strength concrete with specified strength of $150N/mm^2$ and ultra-high strength steel material with tensile strength of $780N/mm^2$. In this paper, the outline of development of an ultra-high strength CFT column is reported. Also, the structural design of the ultra-high-rise building using the CFT columns is reported.

• Journal of Ecology and Environment
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• v.35 no.3
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• pp.167-175
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• 2012

Coastal sand dune systems are particularly fragile and threaten the environment. However, these systems provide fundamental ecosystem services to the nearby urban areas, acting, for example, as protective buffers against erosion. In this paper, we attempt to classify the biotope types of coastal sand dune ecosystems and select an index for the assessment of the conservation value. The types of biotopes are categorized based on the vegetation map; floras are examined in order to research the effects of hinterlands on coastal sand dunes. In addition, a naturalization rate and an urbanization index for each biotope type in hinterlands are analyzed. In the ecosystem of coastal sand dunes, the urbanization index and naturalization rate shows a higher value in sand dunes with areas of road, residential, and idle land in farm villages, rice fields, and fields. On the contrary, a lower value in the urbanization index and naturalization rate is present when typical biotope types, such as sand dune vegetation and natural Pinus thunbergii forests, are widely distributed. Based on these results, urbanization index and naturalization rate should be used as critical indices for the assessment of the ecosystem of costal sand dunes.

• Journal of Environmental Science International
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• v.21 no.4
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• pp.437-450
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• 2012

This study was carried out to investigate the flora of Is. Gageo (Jeollanam-do). The vascular plants were collected 13 times (from June 2008 to September 2011), and 465 taxa in total were identified, including 112 families, 301 genera, 402 species, 3 subspecies, 49 varieties, 9 forms and 2 hybrids. 171 taxa were first records for the region. Among them were seven taxa of Korean endemic plants and the Ministry of Environment-designated plants, which should be protected by the wildlife protection law, were identified as three taxa. There were 54 taxa of the flora with the levels III, IV, V in the floristic indicator plants which was designated by Ministry of Environment. The naturalized plants were identified as 29 taxa, and their naturalization ratio and urban index were found to be 6.2% and 9.0% respectively. There existed many kinds of plants resources having conservational value like $Loxogramme$ $salicifolia$, $Sarcandra$ $glabra$, $Osmanthus$ $insularis$, $Saussurea$ $polylepis$, $Carex$ $ligulata$ var. $austrokoreensis$, $Hosta$ $jonesii$, $Cyrtosia$ $septentrionalis$, etc., in this area. As therefore clear that appropriate plans to conserve the natural habitat of Is. Gageo must be made immediately.

• International Journal of High-Rise Buildings
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• v.1 no.3
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• pp.169-179
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• 2012

The development history, the current situation and the future of the performance-based seismic design of building structures in China are presented in this paper. Firstly, the evolution of performance-based seismic design of building structures specified in the Chinese codes for seismic design of buildings of the edition 1974, 1978, 1989, 2001 and 2010 are introduced and compared. Secondly, in two parts, this paper details the provisions of performance-based seismic design in different Chinese codes. The first part is about the "Code for Seismic Design of Buildings" (GB50011) (edition 1989, 2001 and 2010) and "Technical Specification for Concrete Structures of Tall Building", which presents the concepts and methods of performance-based seismic design adopted in Chinese codes; The second part is about "Management Provisions for Seismic Design of Outof-codes High-rise Building Structures" and "Guidelines for Seismic Design of Out-of-codes High-rise Building Structures", which concludes the performance-based seismic design requirements for high-rise building structures over the relevant codes in China. Finally, according to those mentioned above, this paper pointed out the imperfections of current performance-based seismic design in China and proposed the possible direction for further improvement.