• Proceedings of the Korea Concrete Institute Conference
• /
• 2003.05a
• /
• pp.121-126
• /
• 2003

The objective of this research is to evaluate of seismic performance for reinforced concrete bridge piers with lap splices of longitudinal reinforcement steels using predicting of nonlinear hysteric behavior. For the purpose, enhanced analytical trilinear hystretic model has been proposed to simulate the force-displacement hysteretic curve of RC bridge piers under repeated reversal loads. The moment capacity and corresponding curvature in the plastic hinge have been determined, and the enhanced hysteretic behavior model by five different kinds of branches has been proposed for modeling the stiffness variation of RC section under cyclic loading. The strength and stiffness degradation index are introduced to compute the hysteretic curve for various confinement steel ratios, In addition, the modified curvature factor has been introduced to forecast of seismic performance of longitudinal steel lap spliced and retrofitted specimens. The results of this research will be useful to predict of seismic performance for longitudinal steel with lap spliced and its retrofitted specimens.

• Structural Engineering and Mechanics
• /
• v.41 no.4
• /
• pp.479-494
• /
• 2012

This study explores a coefficient-based seismic capacity assessment method with a special emphasis on low-rise masonry in-filled (MI) reinforced concrete (RC) buildings subjected to earthquake motion. The coefficient-based method without requiring any complicated finite element analysis is a simplified procedure to assess the maximum spectral acceleration capacity of buildings. This paper first compares the fundamental periods of MI RC structures obtained, respectively, from experimental period data and empirical period-height formulas. The coefficient-based method for low-rise masonry buildings is then calibrated by the published experimental results obtained from shaking table tests. The comparison of the experimental and estimated results indicates that the simplified coefficient-based method can provide good approximations of the maximum spectral accelerations at peak loads of the low-rise masonry reinforced concrete buildings if a proper set of drift factors and initial fundamental vibration periods of structures are used.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 1999.10a
• /
• pp.220-227
• /
• 1999

The Purpose of this paper is to evaluate the buckling strength of conceptually designed KALIMER reactor vessel. For evaluation of the buckling load buckling load the design equations and the finite element analysis are used. In finite element method the eigenvalue buckling analysis nonlinear elastic buckling analysis using snap-through buckling method and nonlinear elastic-plastic buckling analysis are carried out. the calculated buckling loads of KALIMER reactor vessel using the finite element method are in well agreement with those of the design equations. From the calculated results of buckling load in KALIMER rector vessel it is shown that the plasticity of vessel materials significantly affects the buckling load but the initial imperfection has little effects, In checking the limits of bucking load of KALIMER reactor vessel using the ASME B & PV Section III. Subsection NH the non-seismic isolation design can not satisfy the buckling limit requirements but the seismic isolation design can sufficiently satisfy the requirements.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.5 no.2
• /
• pp.155-162
• /
• 2001

In this study a structure with viscoelastic and viscous dampers with identical damping coefficient subjected to stationary seismic and wind load were analyzed in time and frequency-domain to compare motion control capability of viscous and viscoelastic dampers. The dampers were placed based on story drift and acceleration obtained from RMS responses. According to the analysis results, the motion control capability of viscous dampers turned out to be superior to that of the viscoelastic dampers for the case of seismic load. On the contrary, in case of wind load, the viscoelastic dampers were more effective in the mitigation of dynamic responses. However, it was also found that the differences were in a narrow margin.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.05a
• /
• pp.207-210
• /
• 2005

The objective of this research is to evaluate of seismic performance for reinforced concrete bridge piers with lap splices of longitudinal reinforcement steels using predict of nonlinear hysteric behavior. For the purpose, analytical trilinear hysteretic model has been used to simulate the force displacement hysteretic curve of RC bridge piers under repeated reversal loads. The moment capacity and corresponding curvature in the plastic hinge have been determined, and the enhanced hysteretic behavior model by five different kinds of branches has been proposed for modeling the stiffness variation of RC section under cyclic loading. The strength and stiffness degradation index are introduced to compute the hysteretic curve vary confinement steel ratio. In addition, the modified curvature factor has been introduced to forecast of seismic performance of longitudinal steel lap spliced and retrofitted specimens.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1996.04a
• /
• pp.157-164
• /
• 1996

Analyses of linear sloshing modes and seismic responses for cylindrical vessel containing fluid are performed by general finite element computer program, ANSYS. In order to examine the effectiveness of the sloshing analysis procedure, the calculated results are compared with experimental ones in the literature. Liquid sloshing effects in cylindrical LNG vessel are analyzed and the fluid-structure interaction effects are evaluated under the seismic loads. The sloshing frequencies calculated agree well with experimental results. The forces and moments for fixed and isolated LNG vessel are also calculated to evaluate the sloshing effects.

• Structural Engineering and Mechanics
• /
• v.54 no.4
• /
• pp.809-827
• /
• 2015

In this paper, seismic energy response of inelastic steel structures under earthquake excitations is investigated. For this purpose, a numerical procedure based on nonlinear dynamic analysis is developed by considering material, geometric and connection nonlinearities. Material nonlinearity is modeled by the inversion of Ramberg-Osgood equation. Nonlinearity caused by the interaction between the axial force and bending moment is also defined considering stability functions, while the geometric nonlinearity caused by axial forces is described using geometric stiffness matrix. Cyclic behaviour of steel connections is taken into account by employing independent hardening model. Dynamic equation of motion is solved by Newmark's constant acceleration method in the time history domain. Energy response analysis of space frames is performed by using this proposed numerical method. Finally, for the first time, the distribution of the different energy types versus time at the duration of the earthquake ground motion is obtained where in addition error analysis for the numerical solutions is carried out and plotted depending on the relative error calculated as a function of energy balance versus time.

• Nuclear Engineering and Technology
• /
• v.25 no.1
• /
• pp.28-36
• /
• 1993

Much effort is being done to standardize the PWR-type nuclear power plant in Korea. This paper presents the development of seismic design criteria for the reactor internals as a part of the standardization program for nuclear power plant. The seismic design loads of the reactor internals are calculated using the reference input motions of reactor vessel taken from Yong-gwang Nuclear Power Plant Units 3 and 4. An overview of analysis related to the basic parameters and methodologies is presented. Also, the response of internal components for the reactor vessel motions is carefully investigated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.11a
• /
• pp.525-525
• /
• 2005

This study is for the seismic analysis and the structural integrity evaluation of the box beam for supporting nuclear fuel-transfer-basket of the HANARO reactor pool. For performing the seismic analysis and evaluating the structural integrity in air or submerged condition, the finite element model of the fuel-transfer-basket and its supporting box beam(the coupled model) was developed. The hydrodynamic effect is also considered by using added mass concept. The seismic response spectrum analyses of the coupled model under the design floor response spectrum loads of Safe Shutdown Earthquake(SSE) were performed. Through the numerical experiments, the analysis results show that the stress values of the coupled model lot the structural integrity are within the ASME Code limits.

• Earthquakes and Structures
• /
• v.10 no.3
• /
• pp.613-628
• /
• 2016

The effectiveness of the use of modern repair schemes for the seismic retrofit of existing RC structures were assessed on a comparative experimental study of carbon fiber-reinforced polymer (CFRP) strips and sheets for the repair of reinforced concrete members of RC frames, damaged because of cyclic loading. Two virgin, single - story, one - bay, 1/3 - scale frame specimens were tested under cyclic horizontal loading, up to a drift level of 4%. Then, virgin specimens, B and F, respectively, were repaired and retested in the same way. One, specimen RB, was repaired with epoxy injections and CFRP strips and one, specimen RF, was repaired with epoxy injections and CFRP sheets. The two specimens are used to examine the differences between the structural behavior of frames repaired using CFRP strips and frames repaired using CFRP sheets. Both qualitative and quantitative conclusions, based on the observed maximum loads, loading and reloading stiffness, hysteretic energy absorption and failure mechanisms are presented and compared. The repaired frames recovered their strength, stiffness and energy dissipated reasonably. The use of CFRP sheets was found more effective than CFRP strips, due to the proper anchorage.