• Earthquakes and Structures
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• v.18 no.4
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• pp.437-449
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• 2020

It is quite apparent that engineering concerns related to the influence of masonry infills on seismic behavior of reinforced concrete (RC) structures is likely to remain relevant in the long term, as infill walls maintain their functionalities in construction practice. Within this framework, the present paper mainly deals with the issue in terms of modal expansion of effective earthquake forces and the resultant modal responses. An adequate determination of spatial distribution of effective earthquake forces over the height of the building is highly essential for both seismic analysis and design. The possible influence of infill walls is investigated by means of modal analyses of two-, three-, and four-bay RC frames with a number of stories ranging from 3 to 8. Both uniformly and non-uniformly infilled frames are considered in numerical analyses, where infill walls are simulated by adopting the model of equivalent compression strut. Consequently, spatial distribution of effective earthquake forces, modal static base shear force response of frames, modal responses of story shears from external excitation vector and lateral floor displacements are obtained. It is found that, infill walls and their arrangement over the height of the frame structure affect the spatial distribution of modal inertia forces, as well as the considered response quantities. Moreover, the amount of influence varies in stories, but is not very dependent to bay number of frames.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.7 no.2
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• pp.51-59
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• 2011

Storage and transfer heat in soils are governed by the soil thermal properties and these properties are therefore needed in many engineering applications, including horizontal ground heat exchanger for ground-coupled heat pumps. This paper presents the measured results of the thermal diffusivity of soils(silica, quartzite, limestone, sandstone, and masonry soils) used for the trench backfilling materials of the horizontal ground heat exchanger. To assess this thermal property, we (i) measure the soil thermal conductivities and volumetric heat capacities using dual-probe method and (ii) compare the estimates from the de Vries method of summing the heat capacities of the soil constituents. The results show that the thermal diffusivity tends to increase as dry soil begins to wet, but it approaches a constant value or even decreases as the soil continues to wet. Measurements made by using the dual-probe method agreed well with independent estimates obtained using the single-probe method.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.1
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• pp.15-22
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• 2018

Raymond, who adopted Le Corbusier's Errazuris House Project, built Karuizawa Villa by incorporating Japan's aspiration for Western modern architecture and strong convictions regarding the preservation of traditional culture heritage, which were prevalent in Japan at the time. Despite the controversy over his plagiarism, Karuizawa Villa shows several unique architectural characteristics. First, in terms of the arrangement and access system, the villa has a common space that affords a view of the lake by accessing from the mountain side. Second, in terms of spatial composition, the common space is connected to the mesonnette by placing a trail to enable enjoyment of natural scenery. In particular, personal space is planned in the shape of a cross by connecting several surfaces to the outside in order to secure enjoyment of the natural environment. Lastly, in the aspect of structure and materials, both architectural buildings adopted masonry by using natural stone as well as building materials suitable for each region and climate by using logs in constructing the main columns and beams. Through Karuizawa Villa, Raymond is considered to have established his own style by combining the standard of Western modern architecture and the elements of Japanese traditional architecture while valuing local architectural technology.

• Earthquakes and Structures
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• v.23 no.1
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• pp.75-85
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• 2022

The megacity Istanbul was struck by an earthquake on September 26, 2019, with a moment magnitude (Mw) of 5.8. The mainshock was followed by many aftershocks. Although the peak ground acceleration (PGA) of the mainshock was as low as 0.08 g, its effect has been more than expected. The intensive reconnaissance studies were accomplished in the highly populated Zeytinburnu and Pendik districts of Istanbul. While the earthquake (EQ) was relatively smaller concerning record-specific intensity measures; the damages such as concrete spalling in reinforced concrete (RC) members, detachment and diagonal cracking of infill walls in RC frames as well as cracks in masonry structures were reported from non-engineered and some engineered buildings. Many studies in the literature state that record-specific intensity measures are not sufficient to evaluate the seismic performance of the structures. The structure-specific intensity measures, soil characteristics, as well as significant duration, energy, and frequency content of EQs should be considered for the evaluation. Dependently, the frequency and energy contents of the Istanbul Earthquake are evaluated to discuss the possible reasons for the perceived effects and the damages. It is concluded that the EQ caused resonance effects on a variety of structures because of its complex frequency content as well as rather low building quality.

• Journal of the Korea Institute of Building Construction
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• v.4 no.4
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• pp.117-126
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• 2004

Construction industry is faced with the problems such as the quickly changeable circumstance and increasing construction companies due to regulation mollification of company registration. In order to overcome these problems, new estimation system based on historical estimation cost is ready to introduce by government step by step. But the time of transition for estimation system causes another problems such as chaos addition to simultaneity of a standard of estimation system and new estimation system, lack of related regulation, accumulation of historical extensive cost data, and adjustment methodology when historical estimation data is applied to next projects. The purpose of this study is to suggest the change factors by activities for estimating historical cost for apartment housing projects. New estimation system is based on historical construction data. For application of this system, the standard adjustment methodology system is necessary. and extensive cost data should be accumulated under an unified construction work classification system. Therefore in this study, according to the construction work classification system, every apartment housing project was classified to 16 work classifications, and 7 major composed items which occupy more than 85% of construction costs are analyzed by detailed activities and by average ratio and maximum ratio each of them. In the result of the study, furniture work, foundation work and masonry work are the works which have big gap of costs between average ration and maximum ratio. In addition to suggestion of change factor by work species, 5 qualified construction specialists are interviewed and change factors in 7 major works are analyzed.

• Journal of the Korea Institute of Building Construction
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• v.15 no.5
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• pp.491-500
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• 2015

This study investigated defect status by work type, based on the report data of defect inspection results, acquired by consumers' request to safety inspection agencies, before the expiration of legal defect repair warranty period. In fact, the data was not acquired by centering on suppliers, namely, construction companies in relation with the defects becoming causes to increase construction cost of apartments. This study aims to provide objective and basic data for quality improvement at construction stage and for solution to defect disputes. The study results are presented below: (1) The number of defect cases occurring from architectural work among total work types were 1,986, defect occurrence rate was 62.5%, and defect repair cost was KRW $25,851/m^2$, which stood at 78.2% of the total work types. This means the defect occurrence rate and defect repair cost in architectural work are bigger than those of other work types. (2) Major defects in architectural work were revealed in the following order: cracks from frame work, inferior interior finishing work, inferior finishing work of plaster/masonry works, water leak/damage from waterproof work and withering/omission from landscape work. The total repair cost of the major selected defects was KRW $12,220/m^2$, and was analyzed to take up 37% of the total defect repair cost.

• Journal of the Korean Institute of Rural Architecture
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• v.15 no.4
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• pp.35-42
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• 2013

The study aims to investigate general characteristics of Jae-sil from an architectural perspective by grasping location, deployment, structure, and plan composition based on existing inhabited conditions in Jeollabukdo. Results derived from the study are as follows. First, the location of Jae-sil is classified into mountainous and village types, and the two types showed a similar distribution. The village type showed the most distribution in the foot of a mountain in the rear of village, while the mountainous type is close to graveyard. The Jae-sil were mostly exposed to south, southeast, and southeast, which was not significantly different from residence. For deployment of the Jae-sil, a "二" shaped house, where main quarter and gated building are parallel located, can be common, indicating that additional attached building is less required. Second, for the platform out of structural components, coursed masonry was conducted by using natural rocks, and placed were a prop on the platform, first line on processed foot stone, and others on natural foot stone. For pillar, front line round columns, while others square columns. The binding type of the upper part of pillar is dominated by jangyeosujang and sorosujang. For wooden frame structure, 5ryangs were the most distributed, and out of these, 1goju 5ryang was the most generally used. For a roof part, it was composed with gambrel roof with single eave, and the roof was constructed by placing traditional Korean tile roof on the top. Third, for a size of Jae-sil out of plan composition, although the facade and the side of it were presented in a diverse manner, 4 facade rooms and 1.5 side rooms were the most frequently presented, and all Jae-sil were equipped with front ceremonial space. For spatial composition of Jae-sil, main floored hall is placed at the center, and each room is placed on the left and right side to secure space for ancestral rite for participants of it, and for a house with 5 rooms or more, it shows that main floored hall and rooms are weighted from side to side.

• Earthquakes and Structures
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• v.11 no.4
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• pp.629-648
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• 2016

This paper deals with 111 buildings built between 1962 and 1987, from various parts of the city of Osijek, for which, through the collection of documentation, a database is created. The aim of this paper is to provide the first steps in assessing seismic risk in Osijek applying method based on vulnerability index. This index uses collected information of parameters of the building: the structural system, the construction year, plan, the height, i.e., the number of stories, the type of foundation, the structural and non-structural elements, the type and the quality of main construction material, the position in the block and built-up area. According to this method defining five damage states, the action is expressed in terms of the macroseismic intensity and the seismic quality of the buildings by means of a vulnerability index. The value of the vulnerability index can be changed depending on the structural systems, quality of construction, etc., by introducing behavior and regional modifiers based on expert judgments. Since there is no available data of damaged buildings under earthquake loading in our country, we will propose behavior modifiers based on values suggested by earlier works and on judgment based on available project documentation of the considered buildings. Depending on the proposed modifiers, the seismic vulnerability of existing buildings in the city of Osijek will be assessed. The resulting vulnerability of the considered residential buildings provides necessary insight for emergency planning and for identification of critical objects vulnerable to seismic loading.

• Structural Engineering and Mechanics
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• v.17 no.3_4
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• pp.527-537
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• 2004

Consequence-Based Engineering (CBE) is a new paradigm proposed by the Mid-America Earthquake Center (MAE) to guide evaluation and rehabilitation of building structures and networks in areas of low probability - high consequence earthquakes such as the central region of the U.S. The principal objective of CBE is to minimize consequences by prescribing appropriate intervention procedures for a broad range of structures and systems, in consultation with key decision makers. One possible intervention option for rehabilitating unreinforced masonry (URM) buildings, widely used for essential facilities in Mid-America, is passive energy dissipation (PED). After the CBE process is described, its application in the rehabilitation of vulnerable URM building construction in Mid-America is illustrated through the use of PED devices attached to flexible timber floor diaphragms. It is shown that PED's can be applied to URM buildings in situations where floor diaphragm flexibility can be controlled to reduce both out-of-plane and in-plane wall responses and damage. Reductions as high as 48% in roof displacement and acceleration can be achieved as demonstrated in studies reported below.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.1
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• pp.39-46
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• 2017

In this paper, a model updating procedure based on the response surface method combined with the multi-objective optimization was proposed and applied for updating of the FE models representing a low-rise reinforced concrete building before and after the seismic retrofit. The dynamic properties to be matched were obtained from vibration tests using a small shaker system. By varying the structural parameters according to the central composite design, analysis results from the initial FE model using a commercial software were collected and used to produce two regression functions each of which representing the errors in the natural frequencies and mode shapes. The two functions were used as the objective functions for multi-objective optimization. Final solution was determined by examining the Pareto solutions with one iteration. The parameters representing the stiffnesses of existing concrete, masonry, connection stiffness in expansion joint, new concrete, retrofitted members with steel section jacketing were selected and identified.