Seismic capacities of the cable members of Incheon Bridge have been evaluated for the three different levels of earthquake motions, which are 1000-year-return-period(design basis level)), 2400-year-return-perioda and hypothetical maximum earthquake level(A=0.66), respectively. Both response spectrum method and time-history method were adopted for the analyses. The results showed that the cable members of Incheon Bridge has safe seismic capacity even under the maximum hypothetical earthquake which is more than three times higher magnitude of the design basis earthquake
In this study is experiment result of reinforced concrete squat shear walls with deformation capacity and structural strengthening performance. In order to evaluate the seismic performance of squat shear walls, slits with opening was used as a variables. The experimental results show that ductility capacity of reinforced concrete squat shear wall with slits is superior compared to normal reinforced concrete squat shear wall
Under cyclic loading, the shear capacity of reinforced concrete (RC) beam-column connections is significantly decreased by the joint bond-slip and shear cracking as deformation increases. In the present study, Joint shear strength model on the basis of bond-slip was developed to evaluate deformability at the joint shear failure.
Bridge Design Specifications (2005) revision was included for the first time in the seismic isolation design. However, in 2005, it is overly simplified, revised in 2010 to conduct performance test, prototype test, quality test of seismic isolation device. Details standards for scaled model test and quality test of seismic isolation device is required to use a rule is recognized at domestic and foreign. This study was to establish quality control test standards by research and review of test types and test methods of seismic isolation devices.
The change of natural frequency according to seismically damaged reicforced concrete (RC) frames was evaluated by using shaking table test results of full-scale one-span RC frame. As the damages of cracks and yields of reinforcing bars were occurred, the frequency decreased. The frequency got decreased to about a half of the initial frequency when the RC frame specimen collapsed.
In case of spatial structures with different ground condition or time lag occurred by earthquake velocity, multiple support excitation may be subjected to supports of a keel arch structure. In this study, the response of the keel arch structure under multiple support excitation are analyzed by means of the pseudo excitation method. Pseudo excitation method shows that the structural response is divided into two parts, ground displacement and structural dynamic response due to ground motion excitation. It is known that the seismic responses of spatial structure under multiple support excitation are different from those of spatial structure under unique simple excitation.
This paper proposed a new type of seismic damper based on yielding of a cantilever type steel element. The hysteretic behavior and energy dissipation capacity of the proposed damper were investigated via component tests under cyclic loads. The experimental results indicated that the damping device had stable restoring force characteristics and a high energy dissipation capacity.
The purpose of this study is to consider site effect in order to estimate Soil-Structure and attenuation parameters with a greater degree of reliability. Site amplification is calculated by proposed Nakamura (H/V ratio). The site amplifications using acceleration motion were compared at several sites. The result can be used for the study of site classification and removal of the site amplification effects.
The purpose of this paper is to verify the seismic strengthening effect of R/C buildings strengthened with the Carbon Fiber Composite Cable(CFCC). In this study, a three-story R/C building that represents a typical Korean school constructed in the 1980s was selected, and its seismic performance before and after strengthening was evaluated based on the nonlinear dynamic analyses. The result indicated that the seismic strengthening effect of the proposed CFCC method was verified in terms of both strength and ductility demands, compared to the building before strengthening
To evaluate the Natural Period of 5 Story Wooden Pagoda in Korea, vibration test was carried out with the microtremors and synchronized human excitation. The natural period and damping constants were obtained and compared with previous research. From the comparison results, the first natural period of tested 5 Story Wooden Pagoda showed similar value with previous research, and many natural period is occurred.
In this paper, the seismic response characteristics of the structures connected through the expansion joint and the possibility of collision and separation between those structures were examined through nonlinear time history analysis. Through this experiment, the usefulness of the interaction vibration control using a steel body and a damper as connection members was verified as the seismic response behavior of the structures was reduced and the collision and separation between those structures were prevented.
Diagonally reinforced concrete coupling beam has complicated reinforcement details. To solve this problem, it is necessary to develop the alternative reinforcement details. The objective of this study is to investigate strain characteristics of coupled shear wall according to the replacement ratio of headed-bar.
To evaluate the post-earthquake damage status of URM buildings in Korea, damage state level from the Earthquake Disaster Response System is classified and static test results of 20 URM walls, dynamic test results of 1 URM building are analyzed. From the analysis results, damage state, maximum story drift ratio and residual story drift ratio regarding to the each damage state level are suggested.
This study proposed simplified design procedure of friction damper for enhancing structural seismic performance. Friction damper has a nonlinear characteristic as performing stick and slip motion. So that reason, design of friction damper is difficult. For easy design of damper, first, equivalent damping ratio of the friction damper is derived. Second, design procedure is proposed by the equivalent damping ratio. Finally, seismic performance of structure installed with the friction damper is verified by five earthquake data.
Many researches about damage prediction for earthquake have been managed separately in Korea so that it would be managed comprehensively and systematically. Also it is necessary to develop the algorithms of ground for earthquake disaster response system in NEMA. This is a study to improve the reliability for damage estimation. We compared foreign cases to find a development direction which can be applied to the earthquake disaster response system.
The double frame system is composed of existing structure, external retrofit frame and hysteretic steel dampers installed between former two components. The DFS retrofit system dissipates the energy by plastic deformation of steel damper caused by relative displacement due to the differences in stiffness, weight, and eigenperiod of each components. The dynamic test with shaking table was performed to verify the seismic performance of the proposed DFS system
This study provide comparative analysis for process of countries' damage prediction using seismic Risk. It is the objective to analyze advantage and disadvantage of various damage prediction, and suggest national application method.
Many existing building in korea, constructed according to an out-date standard, were found to be inadequate to withstand major earthquake. Accordingly, significant research effort has been devoted to develop and evaluate different strengthening techniques to increase to seismic resistance of R/C structure. In our previous research[1], the galss fiber sheet and carbon fiber brace system for seismic strengthening was developed. In the study, a three-story R/C building that represent a typical Korean school constructed in 1980s was selected, and its seismic performance before and after strengthening was evaluated based on the seismic capacity evalution method.
Connection details were developed for the composite column using high strength steel angles. Load-carrying capacity, deformation capacity, and load transfer mechanism of three beam-to-column joint specimens were evaluated under cyclic load tests. In the experiments, mega columns were used for the application in high-rise buildings
A present LSD(limited state design) code for bridge temperature load have applied a uniform standard for various bridge type. In this study, in order to acquire the calculation effective thermal, a steel box girder bridge section specimen with real size dimension was manufactured. And over a year, the temperature data were measured in the sections. Effective temperature within the cross section according to atmospheric temperature were calculated by this experiment data. The analyzed results was very similar correlation when compared with the effective temperature of the Euro Code. Therefore, the effective temperature which calculated based on the present data could be used as the basic data in order to present to the appropriate design criteria for the thermal loads on the domestic bridge design