교량 안전점검 지표별 내하성능 상관관계 분석

정규산,정규산,서동우,김재환,조한민,박기태,신연우 한국방재안전학회 2022 한국방재안전학회 논문집 Vol.15 No.3

Bridges are a key infrastructure that underpins economic and social activities. In Korea, bridges began to be built with economicdevelopment in the 1970s and were built intensively in the 1980s and 1990s. In recent years, as the number of bridges with a service life ofmore than 30 years is increasing, continuous maintenance is required to ensure the safety of the bridges. In particular, in order to cope withthe aging of bridges, research on technology development such as maintenance using ICT technology, preventive maintenance, life cyclecost reduction, and long life bridge is being actively promoted. This paper presents the results of correlation analysis based on the safetyevaluation data of bridges as part of the research on the development of a model for estimating load-carrying capacity of bridges. As aanalysis result, indicators highly correlated with the load-carrying capacity of the bridge was derived.

FRP Hybrid Bar의 인장 거동 예측

정규산,박기태,서동우,김병철,박준석 한국복합신소재구조학회 2017 복합신소재구조학회논문집 Vol.8 No.4

This paper presents experimental and analytical results for predicting tensile behavior of FRP Hybrid Bar(HYB). In order to confirm the tensile behavior of HYB wrapped with glass fiber reinforced polymer(GFRP) on deformed rebar, direct tensile tests were performed on 8 specimens. The diameter of the HYB was considered as a test variable and the tensile load, displacement, and tensile strain of each specimen were measured by tensile test. In order to predict the tensile behavior of HYB, numerical analysis based on tensile model of each material was performed. The tensile models of reinforcing bar, glass fiber, and resin, which are the constituent materials of HYB, are assumed to be simple shapes according to their material properties. The results of the numerical analysis through the strain compliance condition of each material were compared with the experimental results and both results showed consistent trends. The experimental and analytical ratios for yield and ultimate loads were 1.02 and 1.00, respectively, and the coefficient of variation were 3.61 and 2.54, respectively. However, a maximum of about 9 mm error occurred due to the slip generated by the direct tensile test in the comparison between the experimental results and the analytical results for the tensile displacement.

플랫폼을 통한 교량 내하성능 제공 관련 연구

정규산,서동우,박상기 한국복합신소재구조학회 2024 복합신소재구조학회 학술발표회 Vol.2024 No.04

교량의 내하력을 확인하기 위해서는 외관상태 점검 및 차량재하시험, 유한요소해석 수행이 필요하 다. 규모가 작은 교량은 시간 혹은 비용적인 문제로 인해, 상기 과업을 수행하여 내하력을 확인하기가 어려운 점이 있다. 본 연구에서는 플랫폼을 통해 교량의 정보를 등록하여 데이터의 분석에 의해 추정 내하성능을 제공하기 위한 연구를 수행하였다. 추정 내하성능 결과는 점검진단 보고서 상의 안전성 평 가 데이터를 수집하여 통계 분석에 의한 결과를 제공한다.

직접 인장 실험에 의한 Hybrid Bar의 인장 강도 평가

정규산,박준석,김병철,서동우,박기태 한국복합신소재구조학회 2017 복합신소재구조학회 학술발표회 Vol.2017 No.04

Tensile strength was investigated for hybrid bar (HYB), in this study. HYB is made of both steel reinforcement and glass fiber. Cross section of HYB has a shape in which steel reinforcement wrapped with glass fiber. For the production of HYB, rebar of SD400 class and glass fiber of E class are used as main materials. Vinyl ester resin is used to harden a glass fiber. In order to evaluate for tensile strength of HYB, the direct tensile test was performed about total ten specimens. The length of total specimens is 2,200 mm including the grip. Diameter of HYB according to core diameter was considered as a test variable. Direct tensile test for HYB was performed using a UTM with a capacity of maximum 1,000 kN. Tensile strength and strain were measured for each specimen during the test. From the test results, tensile strength and elastic modulus were 317 ~ 341 MPa, 103 ~ 107 GPa, respectively. Especially, elastic modulus of HYB was improved in comparison with usual GFRP bars such as the Aslan 100 or the V-rod.

FRP Hybrid Bar와 이형 철근의 부착 특성 비교

정규산,박기태,유영준,김병철,박준석 한국복합신소재구조학회 2018 복합신소재구조학회논문집 Vol.9 No.2

This paper presents experimental results for evaluating bond strength of FRP Hybrid Bars(HYB). In order to confirm the bond strength of HYB, direct bond strength tests were performed on 20 specimens. 20 specimens made of deformed steel bars were also tested for relative comparison. HYB and deformed steel bars were embedded in a concrete block with a size of 200 mm and different attachment lengths were applied depending on the diameter of the reinforcing bars. During the test, load and relative displacement(slip) were measured and the load-displacement behaviors of all specimens were analyzed from the measured results. The maximum bond strength of deformed steel bars were higher than that of HYB regardless of its diameter. However, after the maximum load, the deformed steel bars were more dominant than the HYB in the sudden load reduction tendency.

탄소섬유시트로 보강된 RC 보의 부착파괴

정규산,박기태,김병철 한국복합신소재구조학회 2019 복합신소재구조학회 학술발표회 Vol.2019 No.04

TRM의 휨 보강 성능 예측에 관한 수치 해석적 연구

정규산,한상훈,홍기남,박기태,서동우 한국복합신소재구조학회 2017 복합신소재구조학회논문집 Vol.8 No.4

Numerical analysis was performed to evaluate for reinforcing performance of RC beams in flexure strengthened with Textile Reinforced Mortar (TRM) in this study. New bond strength model for TRM based on the model proposed by Teng et al. was suggested to predict the flexural behavior of RC beams and effective stress in accordance with debonding of TRM. And reduce factor of 0.729 was suggested by investigation of results on the bending test of RC beams strengthened with TRM. Reliability of proposed bond strength model was verified through the comparisons between collected test results and predicted results about the ultimate load of RC beams occurred by debonding of TRM. The ratios of predicted results on the total experimental results, the average and coefficient of variation were 1.00 and 0.094, respectively. Also, nonlinear analysis method proposed by Cho et al. was used to predict the displacement at the cross-section of mid-span for RC beams in flexure strengthened with TRM. At the three state of the RC beams such as occurrence of initial flexural crack in tensile concrete, yield of tensile rebar, and ultimate in accordance with debonding of TRM. Displacements of beams were calculated at the three state and load-displacement curves by predicted results were compared to the collected test results.

부분 박리된 CFRP 시트의 인장 응력 평가

정규산,박준석,김병철,서동우,박기태 한국복합신소재구조학회 2018 복합신소재구조학회 학술발표회 Vol.2018 No.04

In this study, tensile stresses of partially delaminated CFRP sheets were analytically evaluated. The analytical model is a 15-m long concrete beam with a rectangular cross-section of 2×3 m and uses 480 2D-plate elements and 5760 3D-solid elements for mesh construction. The elastic modulus of concrete and CFRP sheet used in the analysis are 27,536 MPa and 200,000 MPa, respectively, and the compressive strength of concrete and tensile strength of CFRP sheet are 30.0 MPa and 4,000 MPa, respectively. In order to evaluate the change of the tensile stress due to the delamination of the CFRP sheet, the whole attached model and the partially delaminated model according to the position of delamination were considered. As a result of the finite element analysis, the tensile stress of the entire attached CFRP sheet showed a constant tensile stress on the whole cross section, and the tensile stress of the partially delaminated CFRP sheet showed the maximum tensile stress on the position of delamination. Based on the results of this study, future research will be carried out to optimize the layout and shape of CFRP sheets embedded with optical fiber sensors.

TRM으로 보강된 RC 슬래브의 휨 성능에 관한 실험적 연구

정규산,한상훈,홍기남,고원준,조용인 한국복합신소재구조학회 2016 복합신소재구조학회논문집 Vol.7 No.4

Flexural capacity of a Textile Reinforced Mortar(TRM) was investigated by an experimental study. The test program was accomplished on reinforced concrete(RC) slabs consisted of concrete(average compressive strength of 22.23 MPa) and rebar(strength class of SD400). RC slab had 450 mm and 150 mm in size and 2,600 mm in clear span. Strengthening was accomplished by applying carbon-fiber mesh in layers of mortar. Control slab(unstrengthened) and six slabs strengthened with TRM were fabricated to confirm the reinforcing performance in this study. Test variables considered amount of reinforcement and use of anchorage. As a results, it was validated that the flexural capacity of slabs strengthened with TRM increased from 159.9% to 285.2% according to the amount of TRM compared with unstrengthened slab. Experimental results indicated that there are increase in ductility as well as load carrying and deformation capacities when using multiple layers of textile.

TRC로 휨 보강된 RC 보의 처짐 예측

정규산 ( Jung Kyu-san ),서동우 ( Seo Dong-woo ),박기태 ( Park Ki-tae ),한상훈 ( Han Sang-hoon ),홍기남 ( Hong Ki-nam ) 한국구조물진단유지관리공학회 2017 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.21 No.1

Numerical analysis was performed to predict for deflection of reinforced concrete (RC) beams in flexure strengthened with textile reinforced concrete (TRC) in this study. TRC is new reinforcing material to strengthen for deteriorated RC structures. TRC consists of fiber reinforced polymer (FRP) reinforcement of textile form and concrete using fine aggregate. This paper presents both results and process of nonlinear analysis method for experimental results published in 2015 by Jung et al. Nonlinear analysis method proposed by Cho et al. was used to predict the displacement at the cross-section of mid-span for RC beams in flexure strengthened with TRC. At the three states of the RC beams such as occurrence of initial flexural crack in tensile concrete, the yield of tensile rebar, and ultimate in accordance with debonding of TRM. Displacements of beams were calculated at the three state and load-displacement curves by predicting results were compared to the collected test results. As a result, nonlinear analysis method accurately predicted the deflection of RC beams strengthened with TRC.