• Earthquakes and Structures
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• v.14 no.5
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• pp.449-458
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• 2018

Earthquakes have shown the vulnerability of unreinforced masonry (URM) structures. The aim of this research is to study a technique for in-plane seismic retrofitting of URM walls in which both diagonal and vertical steel strips are added to a single side of a URM wall. Specimens have been tested under quasi-static cyclic lateral load in combination with constant vertical load. The tests show that vertical and diagonal strips cause a significant increase in seismic capacity in terms of both strength (about 200%) and displacement at maximum (about 20%). Furthermore, this technique caused the failure modes of URM walls were influenced.

• Smart Structures and Systems
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• v.13 no.6
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• pp.959-974
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• 2014

Hand-Arm Vibration Syndrome (HAVS) is a group of diseases caused by exposure of the hands to vibration while operating the hand held power tools such as road breaker, drilling machine, demolition hammer in construction works. In this paper, area-changed capacitive micro-accelerometer is designed to measure the vibration exposure on worker's hand when operating a drilling machine on various blocks such as clay block, paver block and solid cement block. The design process includes mathematical modelling of micro-accelerometer and simulations are done using INTELLISUITE 8.6. Experimental results are taken for various blocks surfaces using conventional and micro-accelerometer. Comparisons show that usage of area-changed micro-accelerometer for Hand-arm vibration monitoring provides better sensitivity, which in turn reduces the risk of HAVS in workers.

• Structural Engineering and Mechanics
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• v.22 no.4
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• pp.449-467
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• 2006

Most existing concrete structures in Taiwan are considered nonductile due to insufficient transverse reinforcement and poor detailing of frame elements. Such features are fairly typical for buildings constructed prior to 1997, at which time the local building code was revised based on ACI 318-95. Among these structures, many contain perimeter or partition walls made of concrete or clay brick for architectural purposes. These walls, though treated as non-structural components in common design practice, could affect the structural behavior of the buildings during an earthquake. To study the behavior of such structures under seismic load, experiments were conducted on concrete frames of various configurations to show the force-deformation relationships, damage patterns, and other characteristics of the frames. For further interest, similar units with columns jacketed by carbon-fiber-reinforced-polymer (CFRP) were also tested to illustrate the effectiveness of this technique in the retrofit of concrete frames.

• Structural Engineering and Mechanics
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• v.74 no.1
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• pp.121-128
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• 2020

This paper presents an experimental study on the dynamic characteristics of infilled reinforced concrete (RC) frames. A 1/3-scaled, one-bay, three-storey RC frame was produced and tested by using operational modal analysis (OMA). The experiments were performed on five specimens: one reference frame with no infill walls and four frames with infill walls. The RC frame systems included infill walls made of hollow clay brick, which were constructed in four different patterns. The dynamic characteristics of the patterns, including the frequency, mode shapes and damping ratios in the in-plane direction, were obtained by 6 accelerometers. Twenty-minute records under ambient vibration were collected for each model, and the dynamic characteristics were determined using the ambient vibration testing and modal identification software (ARTeMIS). The experimental studies showed that the infill walls significantly affected the frequency value, rigidity and damping ratio of the RC frame system.

• Earthquakes and Structures
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• v.16 no.3
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• pp.329-348
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• 2019

The main objective of this experimental research was to investigate the Seismic performance of reinforced concrete frames infilled with perforated clay brick masonry wall of a type commonly used in Algeria. Four one story-one bay reinforced concrete infilled frames of half scale of an existing building were tested at the National Earthquake Engineering Research Center Laboratory, CGS, Algeria. The experiments were carried out under a combined constant vertical and reversed cyclic lateral loading simulating seismic action. This experimental program was performed in order to evaluate the effect and the contribution of the infill masonry wall on the lateral stiffness, strength, ductility and failure mode of the reinforced concrete frames. Numerical models were developed and calibrated using the experimental results to match the load-drift envelope curve of the considered specimens. These models were used as a bench mark to assess the effect of normalized axial load on the seismic performance of the RC frames with and without masonry panels. The main experimental and analytical results are presented in this paper.

• Journal of architectural history
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• v.21 no.1
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• pp.171-186
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• 2012

The objective of this study is to find out the recent trends of hanok design based on 58 hanoks appeared in architecture magazines in the last 10 years. The cases are analyzed in terms of location, size, building form, spatial organization, material, roof form, and the ceiling form of living room. The consequences of this study is as follows; Most of the recent hanoks are built in rural area (91.4%), which shows the hanok is not accepted as an urban house type. Hanoks tend to be built in 2 stories whose 2nd floor is smaller than the 1st floor. (34.5%) The preferred size is total floor area of $99.2{\sim}165.2m^2$ (62.0%), 3 rooms (46.6%) with a traditional ondol room (60.3%). The buildings with ㄱ-shape (43.1%) and linear-shape (27.6%) are preferred, and the compact plan type similar with apartment house appears (13.8%). In the roof design that greatly influences the appearance of building, the traditional design factors such as half-hipped roof (55.2%), double eaves (27.6%), and eaves curve tend to be sustained. In terms of spatial organization, most of recent hanoks have double-layed plan (74.2%). The living room mostly has separately defined space. (82.8%) The indoor and outdoor tend to be connected by a narrow wooden veranda (39.7%), while some cases don't have any wooden floor space (48.3%). The entrance is adopted as an important spatial element in front part of building (75.9%), and it influences the appearance of building. The living room, the counterpart of the wooden floor hall in traditional hanok, and kitchen tend to be interiorized. In terms of material, the cement roof tile and red clay brick are preferred. Consequently, the walls of recent hanoks have the image of brick structure rather than the wooden frame structure of traditonal hanok.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.5
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• pp.43-51
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• 2004

Recently, the importance of choosing correct pavement materials has been increasing in urban spaces and streets. Much research regarding the pavement theory and construction method have been conducted, but analysis in terms of human psychological character has not yet been performed. The purpose of this study is to investigate the psychological characters to 12 pavement materials, that are commonly used in our urban spaces and streets. The results of the psychological character for each pavement material can be summarized as follows: 1. The psychological characters to each pavement material were as follows: ① Clay embodies a natural, traditional, soft and intimate psychological character; ② Pebble stone has a natural, hard, cool and intimate psychological character; ③ Turf grass incorporates an intimate and soft psychological character; ④ Ceramic brick has an artificial and hard psychological character; ⑤ Tile pavement has a modern, artificial, hard and cool psychological character; ⑥ Water permeable concrete has a modern and artificial psychological character; ⑦ Flag stone has a natural psychological character; ⑧ Granite has a modern and artificial psychological character; ⑨ Portland concrete has an artificial and hard psychological character; ⑩ Small compacted brick has an artificial, dynamic and modern psychological character; ⑪ Wood block pavement has a natural and traditional psychological character; ⑫ Asphalt concrete pavement has a modern, hard and artificial character. 2. On the results of the cluster analysis regarding psychological indexes for 12 pavement materials, pavement materials were categorized in 3 clusters. Among them, one cluster was mainly used as the most popular pavement material in our urban spaces and streets. From this point of view, psychological character for pavement material in our urban spaces and streets was not as various as we expected. 3. In conclusion, the proper selection of pavement materials was very important and the factors affecting the human psychological character should be considered in the design of urban spaces and streets.

• Korean Journal of Heritage: History & Science
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• v.46 no.2
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• pp.206-219
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• 2013

This study aims to estimate firing temperature and physicochemical properties of the four clay bricks excavated from the Maritime Province of Siberia. Analysis result shows that the specimens are composed of clay, quartz and feldspar, and some specimens include carbonized organic materials which were probably added in order to enhance its physical strength in bricks. Major mineral components of the bricks are quartz, illite and clay minerals. The result identifying the existence of silimanite by XRD suggests that white material of the Koc 1 was painted for a certain purpose. Unlike most specimens which contained hematite, several samples contain Mullite. Such result suggests that some bricks were fired at high temperature. Furthermore, the results from TG analysis which does not display exothermic peak which appears at between $800^{\circ}C$ to $1,000^{\circ}C$ but display endothermic peak at $900^{\circ}C$ and it also confirms that they were exposed at $900^{\circ}C$ or higher.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.1
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• pp.22-28
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• 2019

Cement is a basic material for the construction industry and it requires high temperature sintering when manufacturing cement. $CO_2$ emissions from raw materials and fuels are recognized as new environmental problems and efforts are underway to reduce them. Techniques for reducing $CO_2$ in concrete are also recommended to use blended cement such as blast furnace slag or fly ash. In addition, the construction waste generated in the dismantling of concrete structures is recognized as another environmental problem. Thus, various methods are being implemented to increase the recycling rate. The purpose of this study is to utilize the inorganic raw materials generated during the dismantling of the structure as a raw material for the low carbon type cement binder. Such as, waste concrete powder, waste cement block, waste clay brick and waste textile as raw materials for low carbon type cement binder. From the research results, low carbon type cement binder was manufactured from the raw material composition of waste concrete powder, waste cement block, waste clay brick and waste textile.

• 한국문화재보존과학회:학술대회논문집
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• 2004.10a
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• pp.92-100
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• 2004

The host rocks of brick-shaped stone pagoda in the Bunhwangsa temple are lots of kinds andesitic rocks, which has gone through mechanical and chemical weathering. As the overall observation, the pagoda is serious damages by air pollutants, and the northeast parts show the much advanced state of turning white, while the southeast parts are heavily cracked in the materials. The rocks of brick-shaped pagoda body are in a relatively stable condition of weathering and damage except for the abrasion and cracks of the corners. The rocks of the pagoda roof suffer from more symptoms including multiple peel-offs, exfoliation, cracks forming round lines, and falling off stone pieces. The pagoda roof rocks are dominated by the thriving leafy lichens and mosses, especially, there are higher plants (selaginella involvens, dandelions) taking root actively between the brick stones and content mortar. There are even light gray precipitates like stalactites between the rocks of the body, In particular, the 1st and 2nd floor in the east side and the body parts in the north side are the most serious. Their major minerals are calcite, gypsum and clay minerals. The rocks of the stylobate and the tabernacle in all the four directions are composed mainly of granitic rocks. The materials consisting of the tabernacles show the severe splits and distortion, which causes the structural instability. The stylobate rocks are heavily contaminated by some weeds with the often marks of inorganic contamination by secondary hydroxides. The central part of the east stylobate has been sinking, while that of the 1st floor west stylobate is protruded nesting a line of cracks. Accordingly, the inside of the tabernacle is always humid with the constant introduction of rainwater. The stone lion standing in the southeast and northeast side are alkali granite, while that in the southwest and northwest lithic tuff. Each of the stone lion also coated with various colored lichens, mosses, algae, bacteria and bryophyte. The external materials of the pagoda have deteriorated the functions of the rocks and made the loss, falling off, and biological contamination even worse due to the surface weathering. Thus it's urgent to come up with scientific restoration and conservation measures through clinical tests.