• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.04a
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• pp.414-421
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• 1998

The content of this paper consists of two related subjects. One is the assessment of damages in the existing structure and the other is the evaluation of seismic capacity of the structure with damage. A method is presented for damage assessment of existing structures using the modal data measured at limited points by the inverse medal perturbation technique. For efficient damage assessment, the number of the unknown probable damaged members is reduced for each damage identification by grouping the members in the large structure. The aseismic capacity is evaluated for the structure using the results of damage assessment. An example analysis is carried out for a building structure subjected to different earthquake excitations.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.4
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• pp.731-742
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• 2018

Recently, the construction of the urban area has been rapidly increasing, and the excavation work of the ground has been frequently performed at the upper part of the existing underground structure. Especially, when the structure is constructed after the excavation of the ground, the loading and unloading process is repeated in the lower ground of the excavation so that it can affect existing underground structures. Therefore, in order to maintain the stability of the existing underground structure due to the excavation of the ground, it is necessary to accurately grasp the influence of the excavation and the structure load in the adjoining part. In this study, the effects of the ground excavation and the new structure load on the existing tunnel were investigated by large - scale experiment and numerical analysis. For this purpose, a large model tester with a size reduced to 1/5 of the actual size was constructed, and model tests and numerical analyzes were carried out to investigate the effects of the excavation of the body ground by maintaining the distance between the excavation floor and the tunnel ceiling constant, The impacts were identified. As a result of the study, it was confirmed that the deeper the excavation depth, the larger the influence on the existing tunnel. At the same distance, it was confirmed that the tunnel displacement increased with the increase of the building load, and the ground stress increased up to 2.4 times. From this result, it was confirmed that the effect of the increase of the underground stress on the existing tunnel is affected by the increase of the building load, and the influence of the underground stress is decreased from the new load width above 3.0D.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2006.05a
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• pp.53-54
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• 2006

Recently with increasing interest in the operation of life cycle, building remodeling business is spreading like a fashion. Keeping pace with the trend, the present project carried out the remodeling of an existing neighborhood facility into a religious facility based on the concepts of remodeling, reform and renovation. Basic requirements were overcoming spatial limitations, solving structural problems, meeting various functional needs, and securing a spatial size, and the project designed the interior of the building according to these requirements suggested by the owner. To overcome the low floor height of the existing space, the main sanctuary on the 1st floor had the ceiling in the form of a slant and installed indirect lighting into the resulting gaps, maximizing the depth and width of the space visually. The subsidiary sanctuary on the first basement was finished with red bricks, forming an arch using the bricks, to create religious atmosphere. However, considering the low floor height as in the 1st floor and the ceiling even lowered by the arch structure, the arch was formed threefold and the radius of the curvature of the arch was enlarged to secure a spacious feeling. The outer appearance was finished with granite on existing structure to save the cost of construction. In addition to the use of the finishing material, the structure of the arch and the frame of the opening part and the finishing of the walls were expressed with uneven surface in order to avoid the plainness of the appearance.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.14-15
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• 2018

Logistics facilities are characterized by wide spans and high flooring, most of which are constructed with PC (Precast Concrete) methods to meet a wide range of commercial and industrial needs. However, the PC structure is a pin joint design, and the construction cost is increased due to the restrictions caused by the installation process, and the construction period is lengthened. In order to solve the above problem, SMART Frame, which is a structural system similar to the steel frame structure, was developed by embedding a steel frame at both ends of the PC. The purpose of this study is to analyze the erection time reduction effect of steel connected precast concrete components (SMART frames) for long span and heavy loaded logistics buildings compared to existing PC frames. For this study, a logistics building constructed with pin joint PC components is selected as a case. The result is compared with the existing PC frame to confirm the erection time reduction effect.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.36 no.2
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• pp.165-173
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• 2020

The purpose of this research is to evaluate the health performance of existing buildings which completed green remodeling using the WELL Building Standard developed by Delos in the USA. The features and the level of improvement in health were examined and the results were as follows. As a result of comprehensive evaluation of the health performance of the target building, the health performance after green remodeling improvement was improved by 17.3% compared to before green remodeling. As a result of applying the alternatives for improving health performance, improvements were 22.9% by Alternative 1, 28.8% by Alternative 2, and 28.7% by Alternative 3. If the improvement ratio with respect to the construction cost were compared, Alternative 1 was the best followed by Alternative 2. Finally, the cost effectiveness of improving health performance against construction cost were best in the order of self-closing door installation, airtight seal, and pest inspections.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.151-152
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• 2012

Recently, there are growing interests in building LCCO₂ Assessment to reduce carbon emissions. However, existing methods of assessment system include inefficiency in the process of CO₂ calculation requiring considerable data input. Therefore, the purpose of this study is to develop an efficient building assessment system appropriate to material production in construction stage. To that end, quantity input technology was limited to data mapping. Also quantity calculation based on work breakdown structure and item codes consisted of hierarchical structure that is based on facet classification were analyzed. As a result, connectivity links of quantity calculation and CO₂ functional units through item codes for data mapping, and assessment system including calculation and database parts were developed.

• Steel and Composite Structures
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• v.29 no.3
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• pp.287-299
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• 2018

The purpose of this study is to investigate the effectiveness of damped cable systems (DCS) to mitigate the earthquake-induced responses of a building frame structure. The seismic performance of the DCS is investigated using the fragility analysis and life cycle cost evaluation of an existing building retrofitted with the DCS, and the results are compared with the structure retrofitted with conventional fluid viscous dampers. The comparison of the analysis results reveals that, due to the self-centering capability of the DCS, residual displacement approximately reaches to zero for the structure retrofitted with the DCS. The fragility analysis shows that the structure retrofitted with the DCS has the least probability of reaching the specific limit states compared to the bare structure and the structure with the conventional fluid viscous damper (VD), especially under the severe ground motions. It is also observed that both the initial and the life cycle costs of the DCS seismic retrofitting technique is lesser compare to the structure retrofitted with the VD.

• Smart Structures and Systems
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• v.33 no.4
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• pp.313-323
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• 2024

Deterioration of buildings is one of the biggest problems in modern society, and the importance of a safety diagnosis for old buildings is increasing. Therefore, most countries have legal maintenance and safety diagnosis regulations. However, the reliability of the existing safety diagnostic processes is reduced because they involve subjective judgments in the data collection. In addition, unstructured tasks increase rework rates, which are time-consuming and not cost-effective. Therefore, This paper proposed the method that can calculate the safety grade of deterioration automatically. For this, a DNN structure is generated by using existing precision inspection data and precision safety diagnostic data, and an objective building safety grade is calculated by applying status evaluation data obtained with a UAV, a laser scanner, and reverse engineering 3D models. This automated process is applied to 20 old buildings, taking about 40% less time than needed for a safety diagnosis from the existing manual operation based on the same building area. Subsequently, this study compares the resulting value for the safety grade with the already existing value to verify the accuracy of the grade calculation process, constructing the DNN with high accuracy at about 90%. This is expected to improve the reliability of aging buildings in the future, saving money and time compared to existing technologies, improving economic efficiency.

• Earthquakes and Structures
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• v.8 no.2
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• pp.379-399
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• 2015

Existing building structures can easily present material mechanical properties which can largely vary even within a single structure. The current European Technical Code, Eurocode 8, does not provide specific instructions to account for high variability in mechanical properties. As a consequence of the high strength variability, at the occurrence of seismic events, the structure may evidence unexpected phenomena, like torsional effects, with larger experienced deformations and, in turn, with reduced seismic performance. This work is focused on the torsional effects related to the irregular stiffness and strength distribution due to the concrete strength variability. The analysis has been performed on a case-study, i.e., a 3D RC framed 4 storey building. A Normal distribution, compatible to a large available database, has been taken to represent the concrete strength domain. Different plan layouts, representative of realistic stiffness distributions, have been considered, and a statistical analysis has been performed on the induced torsional effects. The obtained results have been compared to the standard analysis as provided by Eurocode 8 for existing buildings, showing that the Eurocode 8 provisions, despite not allowing explicitly for material strength variability, are conservative as regards the estimation of structural demand.

• Earthquakes and Structures
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• v.9 no.2
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• pp.321-337
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• 2015

Existing building structures can easily present material mechanical properties which can largely vary even within a single structure. The current European Technical Code, Eurocode 8, does not provide specific instructions to account for high variability in mechanical properties. As a consequence of the high strength variability, at the occurrence of seismic events, the structure may evidence unexpected phenomena, like torsional effects, with larger experienced deformations and, in turn, with reduced seismic performance. This work is focused on the reduction in seismic performance due to the concrete strength variability. The analysis has been performed on a case-study, i.e., a 3D RC framed 4 storey building. A Normal distribution, compatible to a large available database, has been taken to represent the concrete strength domain. Different plan layouts, representative of realistic strength distributions, have been considered, and a statistical analysis has been performed on the induced reduction in seismic performance. The obtained results have been compared to the standard analysis as provided by Eurocode 8 for existing buildings. The comparison has shown that the Eurocode 8 provisions are not conservative for existing buildings having a large variability in concrete strength.