• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.04a
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• pp.81-88
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• 1998

During an earthquake, there are three main components of excitation : horizontal excitation of the ground, vertical excitation of the pile due to superstructure feedback produced by vertical excitation of the ground, and the seawater excitation induced by the vertical ground shaking, that is, "the seaquake." These excitations could have effects on the soil plugs in open-ended pipe piles installed at offshore sites. In this study, seaquake excitation induced by the vertical ground shaking was simulated by pulsing the water pressure at the seabed. During a seaquake, due to induced excess porewater pressure and pressure gradients in the soil, the capacity of open-ended pipe piles installed in a simulated sea depth of greater than 220 m was reduced serevely and the soil plugging resistance was degraded by more than 80%. The soil plug was failed because of the upward seepage forces that developed in the soil plug due to excess pore water pressure produced in the bottom of the soil plug during the seaquake. The compressive capacity of an open-ended pile in a simulated sea depth of less than 220m was reduced only by about 10%, and the soil plug resistance was degraded by less than 5%.s than 5%.

• Steel and Composite Structures
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• v.24 no.3
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• pp.369-382
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• 2017

This study investigates the reliability of the performance levels of moment resisting steel frames subjected to lateral loads such as wind and earthquake. The reliability assessment has been performed with respect to three performance levels: serviceability, damageability, and ultimate limit states. A four-story moment resisting frame is used as a typical example. In the reliability assessment the uncertainties in the loadings and in the capacity of the frame have been considered. The wind and earthquake loads are assumed to have lognormal distribution, and the frame resistance is assumed to have a normal distribution. In order to obtain an appropriate limit state function a linear relation between the loading and the deflection is formed. For the reliability analysis an algorithm has been developed for determination of limit state functions and iterations of the first order reliability method (FORM) procedure. By the method presented herein the multivariable analysis of a complicated reliability problem is reduced to an S-R problem. The procedure for iterations has been tested by a known problem for the purpose of avoiding convergence problems. The reliability indices for many cases have been obtained and also the effects of the coefficient of variation of load and resistance have been investigated.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.53-56
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• 2004

Recently, post tension flat plate slab system is widely used for a new slab structural system. Slab-column connections may fail in brittle manner by punching shear. Flat plate slabs have been widely used for gravity load resisting system in buildings. Lateral resistance usually provided by shear walls or moment resisting frames. Since plat plates move together with lateral loading system during earthquake or wind, it is important to evaluate the gravity resistance under a drift experienced by lateral force resisting system during either design earthquake or wind. Thus, this study investigated post tension flat plate slab systems whether they have sufficient strength and deformability to resist gravity loads during specified drift levels. Experimental research was carried out.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2006.03a
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• pp.233-240
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• 2006

An experimental investigation on the behavior of reinforced concrete coupling beams is presented. The test variables are the span-to-depth ratio, the ratio of flexural reinforcement and the ratio of shear rebar. The distribution of arch action and truss action which compose the mechanism of shear resistance is discussed. This study proposes the deformation model for reinforced concrete coupling beams considering the bond slip of flexural reinforcement. The yielding of flexural reinforcements determines yielding states and the ultimate states of reinforced concrete coupling beam are defined as the ultimate compressive strain of struts and the degradation of compressive strength due to principal tensile strain of struts. It is expected that this model can be applied to displacement-based design methods.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.677-682
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• 1999

In this paper, the basic concepts and main characteristics in Eurocode 8, which deals with earthquake-resistant design, are reviewed regarding the design of reinforced concrete structures. Eurocode uses the limit-state design method to satisfy the requirements of safety and serviceability. This kind of information can serve to establish the up-coming Korean seismic code which is comprehensive and appropriate to the moderate seismicity region by constituting an important part in the basic data-pool.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.93-98
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• 2000

The objective of this study is to investigate the results of researches which have been conducted throughout the world and in Korea concerning the behavior modes of masonry infill panels and frames. The influence of masonry infill panels on the seismic behavior of RC frames must be considered in the design and evaluation procedure though current code provisions do not generally require explicitly this consideration. However, since the level of the earthquake intensity in Korea is assumed to be moderate, the masonry infill panels may cause the different effect to the structure from those in high seismicity region and this difference should be studied in depth in the future.

• The magazine of the Korean Society for Advanced Composite Structures
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• v.5 no.2
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• pp.15-18
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• 2014

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.5
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• pp.543-550
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• 2010

Earthquake resistant design should provide a description of the structural failure mechanism under earthquakes as well as satisfy the requirement of other designs, e.g. design strengths of each structural member should be equal or greater than the required strengths. The reason of such a requirement is the randomness of seimic loads different from other loads. In this study, a typical bridge is selected as an analysis bridge and the procedure is given to get the ductile failure mechanism through connection design. It is shown with the procedure that the earthquake resistant capacity can be ensured within structural member's strengths required by other designs, without cost raise by strength increase of structural members or by use of shock absorbing device e.g. shock transfer unit.

• Steel and Composite Structures
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• v.23 no.1
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• pp.53-66
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• 2017

Structures submitted to Fire-After-Earthquake loading situations, are first experiencing inelastic deformations due to the seismic action and are then submitted to the thermal loading. This means that in the case of steel framed structures, at the starting point of the fire, plastic hinges have already been formed at the ends of the beams. The basic objective of this paper is the evaluation of the rotational capacity of steel I-section beams damaged due to prior earthquake loading, at increased temperatures. The study is conducted numerically and three-dimensional models are used in order to capture accurately the nonlinear behaviour of the steel beams. Different levels of earthquake-induced damage are examined in order to study the effect of the initial state of damage to the temperature-evolution of the rotational capacity. The study starts with the reference case where the beam is undamaged and in the sequel cyclic loading patterns are taken into account, which represent earthquakes loads of increasing magnitude. Additionally, the study extends to the evaluation of the ultimate plastic rotation of the steel beams which corresponds to the point where the rotational capacity of the beam is exhausted. The aforementioned value of rotation can be used as a criterion for the determination of the fire-resistance time of the structure in case of Fire-After-Earthquake situations.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.1
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• pp.19-26
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• 2018

After the Gyeongju earthquake, school buildings were designated as earthquake shelters. However, the ratio of designed for seismic of domestic school buildings is only 23.2% in Korea, and it is necessary to secure the seismic safety of those. Therefore, in this paper, a target building was selected before the seismic design criteria was established and the seismic performance of the building was evaluated. After the evaluation, reinforcement of the building was carried out using seismic retrofit systems which was previously tested. For this purpose, the evaluation was carried out using OpenSees program and the reliability of the seismic retrofit systems was also verified. In this way, we can more precisely reproduce the response of the building in case of actual earthquake and predict damage of the earthquake in the future.