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Title |
Analytical Evaluations of the Retrofit Performances of Concrete Wall Structures Subjected to Blast Load
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Authors |
김호진 ; 남진원 ; 김성배 ; 김장호 ; 변근주 |
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Keywords |
폭발하중 ; 섬유복합재 ; 보강성능 ; HFPB 유한요소해석 ; 콘크리트 벽체 |
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Abstract |
In case of retrofitting a concrete structure subjected to blast load by using retrofit materials such as FRP (fiber-reinforced polymer), appropriate ductility as well as raising stiffness must be obtained. But the previous approximate and simplified models, which have been generally used in the design and analysis of structures subjected to blast load, cannot accurately consider effects on retrofit materials. Problems on the accuracy and reliability of analysis results have also been pointed out. In addition, as the response of concrete and reinforcement on dynamic load is different from that on static load, it is not appropriate to use material properties defined in the previous static or quasi-static conditions to in calculating the response on the blast load. In this study, therefore, an accurate HFPB (high fidelity physics based) finite element analysis technique, which includes material models considering strength increase, and strain rate effect on blast load withvery fast loading velocity, has been suggested using LS-DYNA, an explicit analysis program. Through the suggested analysis technique, the behavior on the blast load of retrofitted concrete walls using CFRP (carbon fiber-reinforced polymer) and GFRP (glass fiber-reinforced polymer) have been analyzed, and the retrofit capacity analysis has also been carried out by comparing with the analysis results of a wall without retrofit. As a result of the analysis, the retrofit capacity showing an approximate 26~28% reduction of maximum deflection, according to the retrofit, was confirmed, and it is judged that the suggested analysis technique can be effectively applicable in evaluating the effectiveness of retrofit materials and techniques.
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