5 results on '"Shin, Jiuk"'
Search Results
2. Finite element analysis-based blast and seismic performance evaluation for RC frame with retrofitted ENTA damper systems.
- Author
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To, Quoc Bao, Shin, Jiuk, Kim, Jaeyoung, Han, Sang Whan, and Lee, Kihak
- Subjects
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BLAST effect , *SEISMIC response , *STRUCTURAL frames , *TRANSVERSE reinforcements , *REINFORCED concrete , *CONCRETE columns , *EARTHQUAKE resistant design - Abstract
Blast loading and seismic excitations are widely recognized as the most detrimental occurrences that a building structure may encounter throughout its lifespan. Therefore, this study investigated the retrofitting capacity of external devices (ENTA damper systems) for reinforced concrete (RC) frames in term of enhancing their resistance under the combined effects of blast and seismic loads. This study presents the establishment of finite element (FE) models for retrofitted RC frames with ENTA damper systems through the utilization of the dynamic analysis software LS-DYNA. The investigation involved the validation for blast performance of RC column in order to identify the most effective method for modeling blasts. Additionally, the study aimed to validate the performance of RC frame models through effects of ENTA damper systems under seismic loading. Subsequently, a performance evaluation of RC frame structures was carried out to examine the impact of the ENTA damper systems when subjected to blast loading. The findings of the study indicate that the use of external ENTA damper systems effectively enhanced the rigidity and structural integrity of RC frames, while maintaining their ability to resist deformation. Finally, the damage assessment of blast and seismic performance is investigated based on various parameters such as ductility, drift and energy-based damage limits. • Finding the suitable model blasts based on the blast performance of RC column. • Validating performance of the RC frame models under seismic loading. • Investigating the blast performance of RC frame and retrofitted RC frame. • Considering the damage performance of RC frames under blast and seismic loadings. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Influence of shear‐axial force interaction on the seismic performance of a piloti building subjected to the 2017 earthquake in Pohang Korea.
- Author
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Dang‐Vu, Hoang, Lee, Do H., Shin, Jiuk, and Lee, Kihak
- Subjects
EFFECT of earthquakes on buildings ,TRANSVERSE reinforcements ,SEISMIC testing ,COLUMN design & construction ,SEISMIC response ,EARTHQUAKE engineering ,EARTHQUAKES ,VERTICAL motion - Abstract
This study aims to investigate the influence of shear‐axial force interaction on the seismic performance of a piloti‐type building subjected to the Pohang earthquake. For this purpose, a four‐story piloti‐type building in Pohang, Korea whose columns were brutally damaged by the 2017 Pohang earthquake, one of this country's strongest earthquakes in modern history, was chosen as the object of the study. Columns of this piloti‐type building were designed with insufficient transverse reinforcement, resulting in an increased potential for shear‐axial failure. The piloti‐type building was simulated using Zeus‐NL, an efficient analysis and simulation platform developed for earthquake engineering applications to perform nonlinear time history analysis. A hysteretic shear model in Zeus‐NL capable of accounting for the variation in column axial force was adopted to capture the effect of the shear‐axial force interaction, caused by a combination of horizontal and vertical ground motions. The shear model was validated by comparing the simulated and experimental results. The seismic performance of the piloti‐type building under the effect of the shear‐axial force interaction was compared with that under the shear effect only. Results have indicated that shear effect and shear‐axial force interaction effect significantly reduce column maximum shear force and increase column drift demand. The influence is more intense considering shear‐axial interaction. The seismic response in terms of hysteretic behavior, energy dissipation, and stiffness degradation is presented and discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
4. Experimental assessment and effective bond length for RC columns strengthened with aramid FRP sheets under cyclic loading.
- Author
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To, Quoc Bao, Shin, Jiuk, Lee, Gayoon, An, Hyoseo, and Lee, Kihak
- Subjects
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COLUMNS , *CHEMICAL bond lengths , *CYCLIC loads , *SEISMIC response , *REINFORCED concrete , *ENERGY dissipation , *ARAMID fibers - Abstract
Fiber reinforced polymer (FRP) materials continue to demonstrate outstanding performance for strengthening and repairing reinforced concrete structures. However, one of the most significant problems that still has to be tackled is premature failure brought on by the FRP debonding. This research sought to determine how damaged RC columns could be strengthened with aramid (one type of FRP) composites and how that would affect their seismic responses. To further understand the individual effects of each strengthening material on seismic performance, hysteretic responses, such as strength, ductility, and energy dissipation, were examined and compared. Analytical modeling is validated based on the experimental results. Experimental results are validated with comparative study against other solid experimental results within the broader field. Effective bond length (EBL) is crucial for understanding the bonding between aramid fibers and concrete, however various models have different ways of calculating the value of EBL. Therefore, this research examined earlier experimental investigations of EBL and employing finite element (FE) methods established a novel relationship between the EBL and the aramid-to-concrete bond, based on experimental results. • Experimental assessment with various specimens such as RC columns and RC columns with retrofitted aramid sheets. • Developing the FE model to investigate the response of the structural columns. • Considering the effect of the retrofit system on the RC columns. • Proposing the best-fit empirical model between the effective bond length (EBL) and the aramid-to-concrete bond. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
5. Rapid decision-making tool of piloti-type RC building structure for seismic performance evaluation and retrofit strategy using multi-dimensional structural parameter surfaces.
- Author
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Shin, Jiuk, Choi, Insub, and Kim, JunHee
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RAPID tooling , *EARTHQUAKE hazard analysis , *EARTHQUAKE resistant design , *RETROFITTING , *SEISMIC response , *REINFORCED concrete buildings , *FAILURE mode & effects analysis - Abstract
Piloti-type reinforced concrete building structures have vertically irregular configurations composing a moment frame for parking spaces in the lower story and heavy-weight shear wall system for residential spaces in the upper stories. Due to these vertically irregular configurations, such building structures are governed by a soft-story mechanism, damage concentration on the first story. Since the 2017 Pohang earthquake led to severe damage to the piloti-type building structures on a regional level, a decision-making tool mitigating the seismic damage for future events is needed. This paper aimed to propose a rapid decision-making tool promptly estimating seismic damage with simple information and determining a retrofit scheme using a pre-developed extensive database, i.e., multi-dimensional structural parameter surfaces. The multi-dimensional surfaces were created using a simplified modeling approach with five structural parameters: period, strength ratio, and ductility controlling failure modes as the input, and peak inter-story drift ratio and demand-to-capacity ratio as the output. The proposed methodology was validated using a finite element model for the piloti-type building structure with a soft-story mechanism. The seismic responses detected from the multi-dimensional surfaces have a slight difference from those of the numerical model. Nevertheless, the rapid tool predicted a reasonable agreement with performance evaluation from the finite element simulation. In addition, the rapid tool provided feasible retrofit options to meet target performance using brief structural information. Due to its simplified process, the proposed tool can be implemented to the regional seismic assessment for the residential areas where the piloti-type building structures were highly concentrated. • Seismic vulnerabilities to piloti-type buildings highly concentrated in urban areas due to their vertical irregularities. • Extensive database from simplified numerical models reproducing the seismic vulnerabilities of the piloti-type structures. • Development of a database-based tool for regional seismic damage assessment of the piloti-type buildings. • Validation of the proposed tool with finite element simulation of a vertically-irregular building structure. • Establishment of retrofit schemes for piloti-type building structures with brief structural information. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
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