• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.5
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• pp.271-280
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• 2018

This paper presents a framework for developing aftershock fragility curves for reinforced concrete bridges initially damaged by mainshocks. The presented aftershock fragility is a damage-dependent fragility function, which is conditioned on an initial damage state resulting from mainshocks. The presented framework can capture the cumulative damage of as-built bridges due to mainshock-aftershock sequences as well as the reduced vulnerability of bridges repaired with CFRP pier jackets. To achieve this goal, the numerical model of column jackets is firstly presented and then validated using existing experimental data available in literature. A four-span concrete box-girder bridge is selected as a case study to examine the application of the presented framework. The aftershock fragility curves are derived using response data from back-to-back nonlinear dynamic analyses under mainshock-aftershock sequences. The aftershock fragility curves for as-built bridge columns are firstly compared with different levels of initial damage state, and then the post-repair effect of FRP pier jacket is examined through the comparison of aftershock fragility curves for as-built and repaired piers.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.2
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• pp.91-102
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• 2008

Nondestructive testing techniques have been historically and commonly used to evaluate the quality of existing concrete structures. The techniques utilized included visual inspection, hammer sounding, Schmidt hammer rebounding, and ultrasonic pulse velocity testing including tomographic imaging. Results of the nondestructive tests were used to determine areas to be tested with local destructive tests. These tests included concrete compressive strengths, chloride testing, and petrographic testing. The overall results indicate that inside core of each of the pier caps are healthy. On all of the pier caps, extensive exterior concrete layer rehabilitation needs to be completed. This paper shows the application and interpretation of common nondestructive testing techniques and the consequent repair, rehabilitation, maintenance decisions and safety assesment.

• Magazine of the Korea Concrete Institute
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• v.18 no.1 s.90
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• pp.52-55
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• 2006

• Magazine of the Korea Concrete Institute
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• v.13 no.6
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• pp.60-66
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• 2001

• Magazine of the Korea Concrete Institute
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• v.22 no.6
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• pp.71-76
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• 2010

• Magazine of the Korea Concrete Institute
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• v.16 no.1 s.78
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• pp.91-95
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• 2004

• Computers and Concrete
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• v.6 no.6
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• pp.473-490
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• 2009

This paper presents a new methodology to evaluate the load carrying capacity of deteriorated non-slender concrete bridge pier columns by construction of the full P-M interaction diagrams. The proposed method incorporates the actual material properties of deteriorated columns, and accounts for amount of corrosion and exposed corroded bar length, concrete loss, loss of concrete confinement and strength due to stirrup deterioration, bond failure, and type of stresses in the corroded reinforcement. The developed structural model and the damaged material models are integrated in a spreadsheet for evaluating the load carrying capacity for different deterioration stages and/or corrosion amounts. Available experimental and analytical data for the effects of corrosion on short columns subject to axial loads combined with moments (eccentricity induced) are used to verify the accuracy of proposed model. It was observed that, for the limited available experimental data, the proposed model is conservative and is capable of predicting the load carrying capacity of deteriorated reinforced concrete columns with reasonable accuracy. The proposed analytical method will improve the understanding of effects of deterioration on structural members, and allow engineers to qualitatively assess load carrying capacity of deteriorated reinforced concrete bridge pier columns.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.10a
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• pp.135-139
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• 1991

The Seoul expressway is designed with prestressed concrete box girders. As a construction method, Precast Free Cantilever Method (P.F.C.M) is used which is introduced to Korea first time. Especially, the end spans in each bridge are designed to be constructed by cantilever method using temporary cantilever tendons. And pier and pierhead are prestressed vertically and horizontally.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1707-1711
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• 2008

Landing pier is connect from onshore to offshore with bridge type that a coast structure. The sub-structure is consisted of vertical or batter pile and combined reinforced concrete slab. These days useful design method of quay wall of landing pier type for pile foundation analysis abide by approximate depth of pile supported method, "Harbor and port design criterion, 2005 The ministry of land transport and maritime affairs". The approximate depth of pile supported is calculated two kind of method that one is assume to below depth of 1/$\beta$ from assumed submarine surface and other is 1st fixpoint depth by Chang(1937)'s theory. By this paper, FEM dynamic analysis of 3-dimensions was achieved that it has compared pile fixed end modeling with elastic spring modeling base on winkler theory.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.220-227
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• 2002

This study introduces the fragility analysis method for the safety evaluation of reinforced concrete pier subject to earthquake. Damage probability is calculated instead of the failure probability from definition of the damage state in the fragility curve. Not only the damage model determined by the response of structure subject to earthquake, but also the plastic-damage model which can represent the local damage is applied to fragility analysis. The evaluation method of damage state by damage variable in global structure is defined by this procedure. This study introduces the fragility analysis method considering the features of nonlinear time history behavior of reinforced concrete element and the plastic behavior of materials. At last, This study gives one of the approach method for seismic margin evaluation with the result of fragility analysis to design seismic load.