• Structural Engineering and Mechanics
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• v.65 no.6
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• pp.751-760
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• 2018

Damages in concrete structures due to aging and other factors could be a serious and immense matter. Making the best selection of the most viable and practical repairing and strengthening techniques are relatively difficult tasks using traditional methods of structural analyses. This is due to the fact that the traditional methods used for assessing aging structure are not fully capable when considering the randomness in strength, loads and cost. This paper presents a reliability-based methodology for assessing reinforced concrete members. The methodology of this study is based on probabilistic analysis, using statistics of the random variables in the performance function equations. Principles of reliability updating are used in the assessment process, as new information is taken into account and combined with prior probabilistic models. The methodology can result in a reliability index ${\beta}$ that can be used to assess the structural component by comparing its value with a standard value. In addition, these methods result in partial safety factor values that can be used for the purpose of strengthening the R/C elements of the existing structure. Calculations and computations of the reliability indices and the partial safety factors values are conducted using the First-order Reliability Method and Monte Carlo simulation.

• Journal of the Earthquake Engineering Society of Korea
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• v.25 no.1
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• pp.1-9
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• 2021

Most commercial buildings among existing RC buildings in Korea have a multi-story wall-frame structure where RC shear wall is commonly used as its core at stairways or elevators. The members of the existing middle and low-rise wall-frame buildings are likely arranged in ordinary details considering building occupancy, and the importance and difficulty of member design. This is because there are few limitations, considerations, and financial burdens on the code for designing members with ordinary details. Compared with the intermediate or unique details, the ductility and overstrength are insufficient. Furthermore, the behavior of the member can be shear-dominated. Since shear failure in vertical members can cause a collapse of the entire structure, nonlinear characteristics such as shear strength and stiffness deterioration should be adequately reflected in the analysis model. With this background, an 8-story RC wall-frame building was designed as a building frame system with ordinary shear walls, and the effect of reflecting the shear failure mode of columns and walls on the collapse mechanism was investigated. As a result, the shear failure mode effect on the collapse mechanism was evident in walls, not columns. Consequently, it is recommended that the shear behavior characteristics of walls are explicitly considered in the analysis of wall-frame buildings with ordinary details.

• Journal of KIBIM
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• v.5 no.3
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• pp.1-10
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• 2015

We have researched a character of BIM(Building Information Modeling) and GIS(Geographic Information System) data for integrated utilization of urban spatial data and building data for $CO_2$ reduction. We consider literature on integrated utilization of BIM and GIS and measure method of $CO_2$ in urban spatial unit. Among them without distortion of standard data structure, derive method how to install between BIM and GIS standard data. Rhino & Grasshopper is utilization tools of DB platform. The compatibility with existing BIM and GIS data format, graphic and numeric results can be output at the same time. And using the existing ARCHSIM, it can be easily combined for building energy analysis program. Based on BIM and GIS data to run an energy analysis target on Majang-dong, it could be poly synthetically derived the value information and graphic information.

• Computers and Concrete
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• v.27 no.4
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• pp.343-353
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• 2021

In this study, in order to improve the seismic performance of existing reinforced concrete (RC) framed structures, various external attachment of corner steel frame configurations was considered as a user-friendly retrofitting method. The external steel frame is designed to contribute to the lateral stiffness and load carrying capacity of the existing RC structure. A six-story building was taken into account. Four different external corner steel frame configurations were suggested in order to strengthen the building. The 3D models of the building with suggested retrofitting steel frames were developed within ABAQUS environment using solid finite elements and analyzed under horizontal loadings nonlinearly. Horizontal top displacement vs loading curves were obtained to determine the overall performance of the building. Contributions of steel and RC frames to the carried loads were computed individually. Load/capacity ratios for the ground floor columns were presented. In the study, 3D rendered images of the building with the suggested retrofits are created to better visualize the real effect of the retrofit on the final appearance of the façade of the building. The analysis results have shown that the proposed external steel frame retrofit configurations increased the lateral load carrying capacity and lateral stiffness and can be used to improve the seismic performance of RC framed buildings.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.6
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• pp.233-246
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• 2022

The design and the construction were carried out by installing new caissons on the back or the front of existing caissons to increase the structural stability of caisson breakwaters. In this study, we used the ANSYS AQWA program to analyze the wave forces acting on individual caissons according to the effects of wave-structure interaction when new caissons were additionally installed on existing caisson breakwaters. The wave force characteristics acting on the individual caisson were analyzed according to the distance among caissons in frequency domain analysis. In addition, the dynamic wave force characteristics were closely examined on the basis of the frequency at which the unusual distribution of wave forces occurs in irregular wave conditions using time domain analysis.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.205-210
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• 2007

The existing capacity spectrum method (CSM) is based on the displacement based approach for seismic performance and evaluation. Currently, in the domestic and overseas standard concerning seismic design, the CSM to obtain capacity spectrum from capacity curve and demand spectrum from elastic response spectrum is presented. In the multistory building, collapse is affected more by drift than by displacement, but the existing CSM does not work for story drift. Therefore, this paper proposes an improved CSM to estimate story drift of structures through seismic performance and evaluation. It uses the ductility factor in the A-T domain to obtain constant-ductility response spectrum from earthquake response of inelastic system using the drift and capacity curve from capacity analysis of structure.

• Structural Engineering and Mechanics
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• v.71 no.5
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• pp.563-576
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• 2019

According to The Concrete Centre, in the UK shear walls have become an inseparable part of almost every reinforced concrete frame building. Recently, the construction industry has questioned the need for shear walls in low to mid-rise RC frame buildings. This study tried to address the issue in two stages: The first stage, the feasibility of removing shear walls in an existing design for a residential building where ETABS and CONCEPT software were used to investigate the structural performance and cost-effectiveness respectively. The second stage, the same structure was examined in various locations in the UK to investigate regional effects. This study demonstrated that the building without shear wall could provide adequate serviceability and strength within the safe range defined by Eurocodes. As a result, construction time, overall cost and required concrete volume are reduced which in turn enhance the sustainability of concrete construction.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.121-122
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• 2023

Existing modular research has been mainly focused on S (shelter structure) and I (infill interior finishing material), and considerable research has been conducted, and the results are being proposed. However, in the case of the rest (exterior materials and windows, etc.), existing construction methods and materials are borrowed, and supporting hardware members and insulation materials are constructed on site, which acts as a factor hindering overall shortening of the construction period. That is, since the advantages and characteristics of modularity cannot be utilized in the absence of modular cladding, manufacturing of cladding is required. Therefore, it is necessary to develop a cladding system that can drastically reduce the construction period in factories while considering the structural characteristics of PC modulars.

• The Journal of Engineering Geology
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• v.24 no.4
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• pp.455-461
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• 2014

The Honam-Jeju, Korea-Japan, and Korea-China subsea tunnel construction projects have drawn significant attention since the early 2000s. These subsea tunnels are much deeper than most existing natural shallow sea tunnels linking coastal areas. Thus, the need for developing new technologies for the site selection and construction of deep subsea tunnels has recently emerged, with the launch of a research project titled "Development of Key Subsea Tunnelling Technology" in 2013. A component of this research, an analysis of deep subsea geological structure, is currently underway. A ground investigation, such as a borehole or geophysical investigation, is generally carried out for tunnel design. However, when investigating a potential site for a deep subsea tunnel, borehole drilling requires equipment at the scale of offshore oil drilling. The huge cost of such an undertaking has raised the urgent need for methods to indirectly assess the local geological structure as much as possible to limit the need for repeated borehole investigations. This study introduces an indirect approach for assessing the geological structure of the seafloor through a submarine bathymetry analysis. The ultimate goal here is to develop an automated approach to the analysis of submarine geological structures, which may prove useful in the selection of future deep subsea tunnel sites.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.32-33
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• 2015

As the importance of maintenance of reinforced concrete structure recently has emerged, the attention of durability of structure has been increasing. There are many studies about durability decline especially due to the carbonation. In order to study carbonation progress after surface repair of carbonated concrete, each carbonation penetration velocity from different repair materials of concrete structure is compared through the experiment of carbonation accelerating CO₂ concentration to 100%. As carbonation infiltration progress is predicted through this study, the counterplan of service life evaluation will be prepared on selection of repair materials of concrete structure.