• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.319-326
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• 2000

The purpose of this study is to evaluate seismic performance of reinforced concrete pier columns in Seohae Ground Bridge. Since the bridge was designed before preparing the seismic design specification the bridge columns of hollow hexagonal section were designed and constructed with insufficient seismic reinforcement details such as longitudinal and transverse reinforcement lap-splices. In order to take the necessary measures to improve its seismic performance experimental study was performed by small-scale test for the bridge columns, From the quasi-static test for small-scale column specimens the lap-splices were not critical for overall behavior of the column if sufficient lap-splice-length was provided. The test results of failure mode effective stiffness ductility and equivalent viscous damping ratio are presented.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.267-274
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• 2000

Current seismic design codes for building structures are based on the method which can provide enough capacity to satisfy objected performance level and exactly evaluate the seismic performance of buildings. The capacity spectrum method using the nonlinear static(pushover) analysis is becoming a popular tool for evaluating the seismic performance of existing and new building structures. By means of a graphical procedure capacity spectrum method esimates the performance level of structure by comparing the capacity of structure with the demand of earthquake ground motion on the structure. In the method the relation between base shear estimated by a nonlinear static analysis and horizontal displacement is used. Capacity spectrum is usually expressed as what represent the responses of the equivalent single degree of freedom (ESDOF) system for the building structures. However there are some problems in converting procedures into ESDOF system which include not considering the effect of higher modes of structures. The objective of this paper is to compare and verify existing methods and suggest the modified capacity spectrum for seismic performance evaluation of building structures.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.381-388
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• 2000

The steel piers and the concrete-filled steel piers, in spite of reasonable strength, high ductility, small section, and fast construction, have not been considered as the alternatives to the RC piers even in the highly populated urban area where aseismic safety, limited space and fast construction are indispensably required. In this paper, a steel pier and 4 box type concrete-filled steel piers were tested with the quasi-static cyclic loading to estimate the ductility and the strength. Additional devices such as base rib, turn-buckle, and anchor bolted added at the to increase the ductility with minimum additional cost. The result showed that the concrete filled-in steel piers had higher energy absorbtion and strength than steel piers had, but also showed that slight overlooking in the design and fabrication could lead to the abrupt fracture just after small local buckling at the bottom.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.364-371
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• 2000

The pseudo dynamic test has been carried out so as to investigate the seismic performance of RC bridge piers strengthened with and without glass fiber sheets. The Lessons from severe demage of many infrastructures in Kobe(1995) and Northridge(1996) earthquakes have emphasized the need to develop the retrofit measures to enhance flexural strength, ductility and shear strength of RC bridge piers nonseismically designed before 1992. Therefore, the objective of this experimental research is to investigate the seismic behavior of circular reinforced concrete bridge piers by the pseudo dynamic test. and then to enhance the ductility of concrete piers strengthening with glass fiber sheets in the plastic hinge region. 7 circular RC bridge piers were made in a 1/3.4 scale. Important test parameters are confinement steel ratio, retrofitting. load pattern, etc. The seismic behavior of circular concrete piers under artificial ground motions has been evaluated through strength and stiffness degradation, energy dissipation. It can be concluded that existing bridge piers wrapped with glass fibers in the plastic hinge regions could have enough seismic performance.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.239-244
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• 2000

The necessity of the seismic performance evaluation of existing building structures is raised through the Taiwan earthquake in 1999. In this study, the methods of seismic performance evaluation of existing building structures in U.S.A. and Japan were reviewed, applied them to the three-story office building structures in Seoul. It is found out that it is possible to establish the seismic performance evaluation index of RC structure which meet Korean seismic code. Also it is concluded that if sufficient experimental and analytical data could be obtained, a reliable index for the evaluation of seismic performance of existing structures should be established in Korea.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.192-197
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• 2000

The purpose of this study is to investigate the capacity of columns in the Ordinary Moment Frame (OMF). For this purpose, 3-story building was designed according to Uniform Building Code and ACI building Code.(ACI 318-99) The columns were classified into interior and exterior columns. For each interior and exterior columns, upper and lower parts are modeled by the 2/3 scale experimental specimens. The specimens for lower part columns have lap splice. The interior columns were tested under the constant axial force, while the exterior columns were tested under the fluctuating axial force. Based on the results of the experiments, the conclusion for the capacity of the column is proposed.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.195-202
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• 2002

Lap splices of longitudinal reinforcement steels were practically located in the potential plastic hinge region of most bridge columns that were constructed before the 1992 seismic design provision of Roadway Bridge Design Specification in Korea. The objective of this research is to evaluate the seismic performance of shear-critical reinforced concrete(RC) bridge piers with poor detailing of the starter bars in the plastic hinge region, and to develop the enhancement scheme of their seismic capacity by retrofitting with fiber composites. Seven test specimens in the aspect ratio of 2.5 were made with three confinement ratios and two types of lap splices. Quasi-static test was conducted in a displacement-controlled test mode. A significant reduction of displacement ductility ratios were observed for test columns with lap splices of longitudinal steels.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.258-265
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• 2002

The recent earthquakes in worldwide have caused extensive damage to highway bridge structures. In particular, it has been demonstrated that concrete columns with inadequate lateral reinforcement contributed to the catastrophic collapse of many bridges. The poor detailing of the starter bars in these columns compounded the problem of seismic deficiency. Therefore, this study has been performed to verify the effect of lap spliced longitudinal steel and confinement steel type for the seismic behavior of reinforced concrete bridge piers. Eight concrete columns were constructed with existing scale as diameter, 1.2m and height, 4.8m. 4 confinement steel types were adopted for seismic performance evaluation. All specimens were rested under inelastic cyclic loading while simultaneously subjected to a constant axial load. The longitudinal steel lap-splice is highly effective in seismic performance deterioration of reinforced concrete bridge piers.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.266-274
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• 2002

A typical case where the effects of prying in the base angle type anchorage system with expansion bolt. This connection consists of an angle which is attathed to an equipment cabinet and bolted to a concrete slab via an expantion bolt. A seismic analysis of the cabinet may indicate a vertical load, P, transferred to the vertical leg of the angle due to overturning of the cabinet. Due to the eccentricity, b(e), and the continuous beam action in the base member, the load resisted by the bolt will be amplified by a factor λ. Thus, in this study, experimental evaluation of the anchorage system is executed.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.341-348
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• 2002

This manuscript introduces the Building Standard Law of Japan revised at 2000, June. Recently, The Building Standard Law of Japan was revised into the performance-based design format following the trend of international. The structural performance was evaluated for two limiting states; serviceability and soundness limit state, and safety limit state. The design earthquake forces were determined on the basis of seismic activities of the construction site, taking into consideration (a)characteristics of focal mechanism, (b)amplification by local surfaces geology, and (c)soil-structure interaction, in addition to the properties of the planned building including scale, configuration, foundation system, and structural characteristics.