• Journal of the Korean Geographical Society
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• v.38 no.4
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• pp.591-609
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• 2003

The purpose of this study is to exhibit the characteristics and changes of city network in China through the analyses railway structures and movement of passengers and goods in China. On the basis of accessibility analysis., central China area shows the highest level of accessibility, and it declines toward periphery areas. The center of City network was transfered from the central area to the east. Three main lines from north to south and the central status of main cities remain unchanged. The city network stratum structure of China can be divided into three levels. The first level is in a pattern of linear distribution within provices along main lines. The second level, shows a pattern of strengthened linear distribution and crossed influencial regions. The third level includes 5 areas.

• Steel and Composite Structures
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• v.10 no.4
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• pp.331-348
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• 2010

Ample research effort has been oriented into developing damage indices with the aim of estimating in a reasonable manner the consequences, in terms of structural damage and deterioration, of severe plastic cycling. Although several studies have been devoted to calibrate damage indices for steel and reinforced concrete members; currently, there is a challenge to study and calibrate the use of such indices for the practical evaluation of complex structures. The aim of this paper is to introduce an energy-based damage index for multi-degree-of-freedom steel buildings that accounts explicitly for the effects of cumulative plastic deformation demands. The model has been developed by complementing the results obtained from experimental testing of steel members with those derived from analytical studies regarding the distribution of plastic demands on several steel frames designed according to the Mexico City Building Code. It is concluded that the approach discussed herein is a promising tool for practical structural evaluation of framed structures subjected to large energy demands.

• Journal of Korean Association for Spatial Structures
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• v.14 no.1
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• pp.61-68
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• 2014

The design of foot-bridge is often influenced by natural frequency. Consequently, vibration frequency becomes important. The empirical expressions used to quantify this parameter at the design phase have not been developed enough to give guideline to Korean foot-bridge. This paper is concerned with the vertical natural frequency of steel foot-bridges. It describes the vibration measurement methods employed for testing structures and presents reliable methods of assessing natural frequency from jumping vibration tests. Data from measurements on 16 structures in Seoul are given. Regression formulas of natural frequency for steel-framed foot-bridges are suggested. Finally, obtained formula are compared with empirical expressions of Seoul City's guideline.

• Smart Structures and Systems
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• v.11 no.2
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• pp.217-240
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• 2013

In this paper, practical methods to utilize PZT's dual piezoelectric effects (i.e., dynamic strain and electro-mechanical (E/M) impedance responses) for damage detection in beam-type structures are presented. In order to achieve the objective, the following approaches are implemented. Firstly, PZT material's dual piezoelectric characteristics on dynamic strain and E/M impedance are investigated. Secondly, global vibration-based and local impedance-based methods to detect the occurrence and the location of damage are presented. Finally, the vibration-based and impedance-based damage detection methods using the dual piezoelectric responses are evaluated from experiments on a lab-scaled beam for several damage scenarios. Damage detection results from using PZT sensor are compared with those obtained from using accelerometer and electric strain gauge.

• Computers and Concrete
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• v.25 no.2
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• pp.167-179
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• 2020

Optimal design of structures against earthquake loads is often limited to reduce initial construction costs, while the cost induced to structures during their useful life may be several times greater than the initial costs. Therefore, it is necessary to consider the indirect costs due to earthquakes in the design process. In this research, an integrated methodology for calculating life cycle cost (LCC) of moment-resisting concrete frames is presented. Increasing seismic safety of structures and reducing human casualties can play an important role in determining the optimal design. Costs incurred for structures are added to the costs of construction, including the costs of reconstruction, financial losses due to the time spent on reconstruction, interruption in building functionality, the value of people's life or disability, and content loss are a major part of the future costs. In this research, fifty years of useful life of structures from the beginning of the construction is considered as the life cycle. These costs should be considered as factors of calculating indirect costs of a structure. The results of this work represent the life cycle cost of a 4 story, 7 story, and 10 story moment-resisting concrete frame by details. This methodology is developed based on the economic conditions of Iran in 2016 and for the case of Tehran city.

• Journal of architectural history
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• v.18 no.5
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• pp.59-80
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• 2009

The purpose of this study is to investigate the history, space structures, blueprint, and techniques of the construction of Nam-hea city walls. Nam-hea city walls were relocated in 1439 from Whagumhun-Sansung(火金峴山城) to the present site, nearby Nam-hea Um.(南海邑) The city walls were rebuilt after they were demolished during Japanese invasion on Korea in 1592 and their reconstruction was also done in 1757. At present, the city walls only partially remained due to the urbanization of the areas around them. A plane form of the City wall is a square, and the circumference os approximately 1.3km. According to the literature, the circumference of the castle walls is 2,876尺, the height is 13尺, and the width is 13尺 4寸. Hang-Kyo(鄕校). SaGikDan(社稷壇), YoeDan(厲壇), SunSo(船所) which is a harbor, as well as government and public offices such as Kaek-Sa(客舍) and Dong-Hun(東軒) existed inside the castle walls. Inside the castle walls were one well, five springs, one ditch, and one pond, and in the castle walls, four castle gates, three curved castle walls, and 590 battlements existed. The main government offices inside castle walls were composed of Kaek-Sa, Dong-Hun, and Han-Chung(鄕廳) their arrangements were as follows. Kaek-Sa was situated toward North. Dong-Hun was situated in the center of the west castle walls. The main roads were constructed to connect the North and South castle gate, and subsidiary roads were constructed to connect the East and West castle gate. The measurement used in the blueprint for castle wall was Pobaek-scale(布帛尺:1尺=46.66cm), and one side of it was 700尺. South and North gate were constructed in the center of South and North castle wall, and curved castle walls was situated there. One bastion was in the west of curved castle walls and two bastions were in the east of curved castle walls. The east gate was located in the five eighths of in the east castle wall. Two bastions were situated in the north, on bastion in the south, one bastion in the south, and four bastions in the west castle wall. The castle walls were constructed in the following order: construction of castle field, construction of castle foundation, construction of castle wall, and cover the castle foundation. The techniques used in the construction of the castle walls include timber pile(friction pile), replacement method by excavation.

• Journal of the Korean Institute of Rural Architecture
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• v.11 no.3
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• pp.19-28
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• 2009

This research aimed at showing an improvement direction in the future by analyzing the tendency to select a rural landscape housing and the characteristics centering around the data of the landscape-authenticated housing executed in Chuncheon City from 2005 to 2008. For 4 years, 25 houses in all were authenticated by Chuncheon City after being selected as landscape housing. As the result of analyzing the authenticated 25 housing, lots of landscape houses were located in natural green areas, and small-scale houses of $99m^2$ or less in the house size were preferred. The structures introducing the nature-friendly materials such as wood, yellow earth and clay continued to increase in the house structure. And in the selection of the authenticated houses, the landscape architecture and the harmony with the surrounding environment had a big effect on the selection.

• Steel and Composite Structures
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• v.43 no.2
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• pp.153-164
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• 2022

In this study, a series of cyclic loading tests were performed on viscoelastic dampers (VED) composed of viscoelastic polymer composite material and thin steel plates to observe the variation of the mechanical properties under different loading conditions. A mathematical model was developed based on the Kelvin-Voigt and Bouc-Wen models to formulate the nonlinear force-displacement relationship of the viscoelastic damper. The accuracy of the proposed mathematical model was verified using the data obtained from the tests. The mathematical model was applied to analyze a reinforced concrete framed structure retrofitted with viscoelastic dampers. Nonlinear dynamic analysis results showed that the average maximum inter-story drift ratios of the retrofitted structure met the target limit state after installing the VED. In addition, both the maximum and residual displacements were significantly reduced after the installation of the VED.

• Journal of Ocean Engineering and Technology
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• v.8 no.2
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• pp.80-92
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• 1994

The dynamic response characteristics of a floating ocean city are examined for presenting the basic data for the design of huge offshore structures supported by a large number of floating bodies in waves. The numerical approach which is accurate in linear system is based on combination of a three dimensional source distribution method, wave interaction theory and the finite element method of using the space frame element. The hydrodynamic interactions among the floating bodies are taken into account in their exact form within the context of linear potential theory in the motion and structural analysis. The method is applicable to an arbitrary number of three dimensional bodies having any individual body geometries and geometrical arrangement with the restriction that the circumscribed, bottom-mounted. Imaginary vertical cylinder for each body does not contain any part of the other body. The validity of this procedure was verified by comparing with experimental results obtained in the literature.

• Earthquakes and Structures
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• v.21 no.6
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• pp.653-667
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• 2021

In this study, cyclic loading tests were conducted on the precast concrete (PC) wide beam (WB)-column joints. Two beam-column joint specimens were fabricated with the arrangement and anchorage details of the reinforcing bars penetrating the beam and column as variables. Through a cyclic loading test, the lateral load-story drift ratio responses, seismic performance characteristics (e.g., ductility, overstrength factor), energy dissipation, strength and stiffness degradations of each specimen were compared and analyzed based on the various indices and the current structural codes (ACI 318-19 and ACI 374.1-05 report). In addition, the shear lag effect was confirmed through the gauge values of the PC beam, and the differences in seismic performance between the specimens were identified on that basis.