• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.6
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• pp.455-462
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• 2013

The effects of earthquakes can be devastating especially to existing structures that are not based on earthquake resistant design. This study proposes a steel grid shear wall that can provide a sufficient lateral resistance and can be used as a seismic retrofit method. The pushover analysis was performed on RC structure with and without the proposed steel grid shear wall. Obtain the performance point that the target structure for seismic loads applied to evaluate the response and performance levels. The capacity spectrum at performance point is nearly elastic range, so satisfied the performance objectives(LS level). And response modification factor(R factor) were calculated from the pushover analysis. The R factor approach is currently implemented to reflect inelastic ductile behavior of the structures and to reduce elastic spectral demands from earthquakes to the design level. The R factor increases from 2.17 to 3.25 was higher than the design criteria. As a result, according to reinforcement by steel grid shear wall, strength, stiffness, and ductility of the low-rise RC structure has been appropriately improved.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.5
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• pp.113-120
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• 2020

Safety accidents, called industrial accidents in construction work, are causing a lot of casualties, property damage and social controversy in the event of an accident, causing the construction to lose public confidence. The risk of safety accidents at construction sites may continue to increase as the construction of high-rise, large-scale, and multi-purpose complex buildings has increased in recent years. In particular, the most frequently constructed apartment construction among reinforced concrete buildings is designed and constructed with a wall-like structure with no beams for each floor, while the lower floors are made of lamen with columns and beams. As a result, the transfer beam or transfer slab to withstand the upper load is installed on the upper part of the Ramen structure, so the system Dongbari, which is installed as a temporary material during concrete laying construction, may collapse at any time during plowing and curing. The purpose of this study is to apply IT convergence technology to prevent the collapse of the system Dongbari during concrete installation, and to apply many of the variables that may occur during construction on a case-by-case basis to check the stability of the system Dongbari and to propose a model of the anti-conducting prediction system.

• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.305-313
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• 2012

Unreinforced masonry buildings represent a significant portion of the existing and historical buildings around the world. Recent earthquakes have shown the need for seismic retrofitting for these types of buildings. Various types of retrofitting materials (i.e., shotcrete, ECC and Fiber Reinforced Polymer sheets (FRPs)) for unreinforced masonry buildings (URM) have been developed. Engineers prefer to use FRPs, because these materials enhance the shear strength of the wall without expansion of wall sectional area and adding weight to the total structure. However, the complexity of the mechanical behavior of the masonry wall and the lack of experimental data from walls retrofitted by FRPs may cause problems for engineers to determine an appropriate retrofitting level. This paper investigate in-plane behavior of URM and retrofitted masonry walls using two different types of FRP materials to determine and provide information for the retrofitting effect of FRPs on masonry shear walls. Specimens were designed to idealize the wall of a low-rise apartment which was built in 1970s in Korea with no seismic reinforcements with an aspect ratio of 1. Retrofitting materials were carbon FRP and Hybrid sheets which have different elastic modulus and ultimate strain capacities. Consequently, this study evaluated the structural capacity of masonry shear walls and the retrofitting effect of an FRP sheet for in-plane behavior. Also, the results were compared to the results obtained from the evaluation method for a reinforced concrete beam retrofitted with FRPs.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.6
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• pp.18-26
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• 2010

Outdoor lighting has become a necessary essential part of society for safety and comfortable space. However, inappropriate outdoor lighting leads to energy waste and poor landscape. Outdoor lighting is a very important social element, which enables us to conduct various activities at night in a safe, efficient and comfort way. River Thames in UK, Venice in Italy and Sydney in Australia is a good example of the coastal area. This paper aims to evaluate the light pollution of outdoor lighting in coastal area in Busan city. The Radiant Imaging ProMetric-1400 was used to measure the luminance of Gwangalli Beach, Marine City and Haeundae Beach. Compare to the CIE recommendation level the luminance of the all outdoor lighting were about 2~20 times higher. Outdoor lighting of the building facade luminance level and color should be particularly limited.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.6
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• pp.81-91
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• 2003

Recently, many high-rise reinforced concrete(RC) bearing-wall structures of multiple uses have been constructed, which have the irregularities of weak(or soft) story and torsion at the lower stories simultaneously. The study stated herein was performed to investigate seismic performance of such a high-rise RC structure through a series of shaking table tests of a 1: 12 model. Based on the observations of the test results, the conclusions are drawn as follows: 1) Accidental torsion due to the uncertainty on the properties of structure can be reasonably predicted by using the dynamic analysis than by using lateral force procedure. 2) The mode coupled by translation and torsion induced the overturning moments not only in the direction of excitations but also in the perpendicular direction: The axial forces in columns due to this transverse overturning moment cannot be adequately predicted using the existing mode analysis technique, and 3) the hysteretic curve and the strength diagram between base shear and torque(BST) clearly reveal the predominant mode of vibrations and the failure mode.

• Journal of Korean Society of Steel Construction
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• v.15 no.5 s.66
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• pp.541-549
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• 2003

Split-tee connection with High Strength Bolts is normally used in low and middle rise buildings in Europe because the structural efficiency and installation work of connections are excellent. However, the domestic situation is different from that in Europe. The analysis and the design for the T-split connection are complicated, because the structural behavior often T-split connection with High Strength Bolt is governed by so many parameters, i.e., prying action, bolt's tension, shear failure and plastic failure of flange plates. Many researches regarding the structural behavior of the split-tee connection have been undertaken in other parts of the world, such as the, Americas, Japan and Europe, but in the domestic context, this is a pioneering study. Therefore, the purpose of this paper is to supply basic data for the design of T-split connection, and to verify the structural characteristics that define reactions to prying action, based on an experimental study.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.6
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• pp.205-214
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• 2010

Masonry structures have been used throughout the world for the construction of residential buildings. However, from a structural point of view, the masonry material is characterized by a very low tensile strength. Moreover, the bearing and shear capacity of masonry walls have been found to be vulnerable to earthquakes. In this study, to improve the seismic performance of masonry walls, hexagonal blocks were developed and six masonry walls made with hexagonal block were tested to failure under reversed cyclic lateral loading. This paper focuses on an experimental investigation of different types of wall with hexagonal blocks, i.e. walls with different hexagonal blocks and with different reinforcing bar arrangements, subjected to applied cyclic loads. The cracking, damage patterns and hysteretic feature were evaluated. Results from the hexagonal masonry wall were shown more damage reduction and less brittle failure in comparison to the existing rectangular masonry walls.

• Journal of Navigation and Port Research
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• v.32 no.6
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• pp.505-513
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• 2008

Regarding the developmental plans for the coastal areas and marine architectures, this study deal with the overall planning of apartment complexes in waterfront areas, focusing upon the analysis of their comfort and convenience factors from the perspective of the potential residence. It also analysis the intra-complex comfort and satisfaction conditions in terms of their floor-by-floor, directional. and location factors. The results of the study are as follows: 1) The order of respondents' preference on directional factor has been found to be: South > Southeast > Southwest > East > others. 2) 67% of the people surveyed on scenery responded that outward view is considered more significant than the directional factor. 3) A comprehensive analysis of floor zone-specific view preference shared that there were only minor differences among quay wall, arc, and river-seashore types. The impact of the characteristics of the marine environments turned out to be a greater point of consideration; showing that the other of floor-preference is: high-level > ultra-high level > middle level > low level.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.85-93
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• 2021

The seventy percentage of Korean Peninsular is covered by the mountainous area, and the depth of west sea and south sea is relatively shallow. Therefore, a large scale land reclamation from the sea has been implemented for the construction of industrial complex, residental area, and port and airport facilities. The common problem of reclaimed land is consisted of soft ground, and hence it has low load bearing capacity as well as excessive settlement upon loading on the ground surface. The hollow concrete block has been used to reinforce the loose and soft foundation soil where the medium-high apartment or one-story industrial building is being planned to be built. Recently the earthquakes with the magnitude of 4.0~5.0 have been occurred in the west coastal and southeast coastal areas. Lee (2019) reported the advantages of hollow concrete block reinforced shallow foundation through the static laboratory bearing capacity tests. In this study, the dynamic behavior of hollow concrete block reinforced sandy ground with filling the crushed stone in the hollow space has been investigated by the means of shaking table test with the size of shaking table 1000 mm × 1000 mm. Three types of seismic wave, that is, Ofunato, Hachinohe, Artificial, and two different accelerations (0.154 g, 0.22 g) were applied in the shaking table tests. The horizontal displacement of structure which is situated right above the hollow concrete block reinforced ground was measured by using the LVDT. The relative density of soil ground are varied with 45%, 65%, and 85%, respectively, to investigate the effectiveness of reinforcement by hollow block and measured the magnitude of lateral movement, and compared with the limit value of 0.015h (Building Earthquake Code, 2019). Based on the results of shaking table test for hollow concrete block reinforced sandy ground, honeycell type hollow block gives a large interlocking force due to the filling of crushed stone in the hollow space as well as a great interface friction force by the confining pressure and punching resistance along the inside and outside of hollow concrete block. All these factors are contributed to reduce the great amount of horizontal displacement during the shaking table test. Finally, hollow concrete block reinforced sandy ground for shallow foundation is provided an outstanding reinforced method for medium-high building irrespective of seismic wave and moderate accelerations.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.2
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• pp.69-81
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• 2009

Using a computational fluid dynamics (CFD) model, the effects of building complexes constructed under an urban renewal plan on air flows in an urban area were investigated. For this, the geographic information system (GIS) data were used as the input data of the CFD model and four experiments were numerically simulated for different inflow directions (westerly, southerly, easterly, and northerly cases). Before constructing building complexes under the urban renewal plan, wind speed at the pedestrian level was very low around buildings because of decrease in wind speed by the drag effect of the densely distributed low-rise buildings. As the high-rise buildings were constructed and building density decreased by the urban renewal plan, wind speed at the pedestrian level increased compared to that before the urban renewal plan because the drag effect by the buildings decreases and the channeling effect satisfying the mass continuity partially appeared at the spaces among the high-rise buildings. At the upper levels, wind speed partially increased inside the high-rise buildings due to the channeling effect but it remarkably decreased across a vast extent of the downwind regions due to the generation of the recirculation zone and the drag effect of the high-rise buildings.