Shape Design and Performance Evaluation of FRP Box-type Stiffener For the Application of RC Structure

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(1)한국복합신소재구조학회 논문집 제4 권, 제1 호, 2013 년 03 월 J. Korean Soc. Adv. Com p. Struc. Vol. 4, No. 1, pp. 40-46, M arch 2013 DOI http://dx.doi.org/10.11004/kosacs.2013.4.1.040. 철근콘크리트용. ISSN 2093-5145(Print) ISSN 2288-0232(Online). 휨 보강재의 형상 설계 및 거동 평가 2 권민호1 ·정우영 · Enrico Spacone. 3. 2. 경상대학교 토목공학과 교수1, 강릉원주대학교 토목공학과 교수 Professor, Department of Civil and Architectural Engineering, University "G.D'Annunzio" Chieti-Pescara, Italy. 3. Shape Design and Performance Evaluation of FRP Box-type Stiffener For the Application of RC Structure 3. 2 Kwon, Min-Ho1 · Jung, Woo-Young · Spacone, Enrico 1. Professor, Department of Civil Engineering, Gangneung-Wonju National University, Gangneung, South Korea 2 Professor, Department of Civil Engineering, ERI, Gyeongsang National University, Jinju, South Korea 3 Professor, Department of Civil and Architectural Engineering, University "G.D'Annunzio" Chieti-Pescara, Italy A bstract: This paper presents the design, fabrication and perform ance of a reinforced concrete beam strengthened by GFRP box plate and its possibility for structural rehabilitations. The load capacity, ductility and failure m ode of reinforced concrete structures strengthened by FRP box plate were investigated and com pared with traditional FRP plate strengthening method. This is intended to assess the feasibility of using FRP box plate for repair and strengthening of damaged RC beams. A series of four-point bending tests were conducted on RC beams with or without strengthening FRP system s the influence of concrete cover thickness on the perform ance of overall stiffness of the structure. The param eters obtained by the experimental studies were the stiffness, strength, crack width and pattern, failure m ode, respectively. The test yielded complete load-deflection curves from which the increase in load capacity and the failure m ode was evaluated. Key Words: FRP, RC Structure, Com posite, Flexural Strengthening, Box Plate. (GFRP) (CFRP) CFRP ·. 1. 서 론 FRP ,. , GFRP .. , .. .. FRP Plate. ·. FRP Plate Plate. FRP. .. ·. FRP. · , FRP. ,. FRP ·. FRP . FRP , ,. ·. ,. 주요어: 섬유강화 복합재료, 철근콘크리트 구조 , 복합구조, 휨 보강, 박스형 플레이트 Corresponding author: Jung, Woo-Young Department of Civil Engineering, Gangneung-Wonju National University, 7 Jukhun-gil, Gangneung, 210-702, South Korea. Tel: +82-33-640-2421, Fax: +82-33-646-1391 , E-mail:woojung@gwnu.ac.kr 투고일: 2012년 12월 12일 / 수정일: 2012년 12월 131일 / 게재확정일 : 2013년 1월 18일. 40. Korean Society for Advanced Composite Structures.

(2) Shape Design and Performance Evaluation of FRP Box-type Stiffener For the Application of RC Structure. FRP. ..      . 240 f/. (5). Fig. 2 30mm 50mm J. G. Teng. .. .. FRP. FRP. , FRP Box. Plate .. 2. 이 론. Fig. 2 Shear deformation of beam. . . ,.                     , c d. . .. (5a) ′  .    ′      . .. W +W/2. . D. ,. D. (5b).       상수 . . D. Q ,Q=+W/2 (6).  ≤  ≤   M. .. Q. .            ≤  ≤     ≤  ≤                 ≤  ≤    .  . . .          . . .                      or           ․       . (1) (2) (3) ..             (3). (6b). (7) . Fig. 1 Dimensions of sandwich beam . (6a).            . .. Sandwich core ,    ⇒    10mm ,. 2 core core 30mm. 30mm .. (2). 3. 실 험 (4) 3.1 실험 계획 4. , Vol. 4, No. 1, 2013. 41.

(3) Kwon, Min-Ho · Jung, Woo-Young · Spacone, Enrico. . ). 200 ( )×300 ( 200 ( )×280 ( ) 1 1920 , 2200 50 ,. 3 , .. (FLA-5-11-1L). . (PL-60-11-1L) . DATA. (TDS-303) 30 2-D10. .. 2-D13. . D10@150. 350 .. 4. 결 과 4.1 하중-처짐 관계 비교. Tabel 1. Specimen type No. 시험 체명. 보강재 종류. 1 2 3 4. N 50FP 30FP SB. Plate. LOGGER. .. 보강 길이 (mm) 1860. Box. 피복 두께 (mm) 50 50 30 50. N. . 50FP. 비고 무보강. -. 30FP. . N 50FP. 콘크리트강도 27.2MPa. 79% ,. 20. 30FP , SB. 42% 38% , 50FP. 27% Fig. 4 Standard (N). , SB .. N. . Table 2. 16% 30FP ,. Fig. 6 FRP box (SB) Fig. 8 Load-displacement for specimens. Fig. 7 FRP Plate (30FP). 3.2 실험 방법 1000KN 3 ,. 42. J. Korean Soc. Adv. Comp. Struc. 50FP. Fig. 7 .. Fig. 5 FRP Plate (50FP). ,. .. Fig. 9 Load-strain for specimens.

(4) Shape Design and Performance Evaluation of FRP Box-type Stiffener For the Application of RC Structure. Tabel 2. Results of test 항복 시험 처짐 체명 (mm) N 3.99. 극한 처짐 (mm) 20.32. 항복 하중 (kN) 66.92. 극한 보강 처짐 하중 ** 파괴모드 효과* 량비 (kN) 휨파괴 100.38 1.00 1. 50FP 5.08 21.40 116.52 179.99 1.79. 0.73. 30FP 5.07 21.90 83.90 142.42 1.42. 1.01. SB. 4.28 11.04 85.47 138.92 1.38. 0.84. Fig. 10 Crack pattern for N. 휨+중아부 계면 박리파괴 휨+중아부 계면 박리파괴 휨 전단 균열의 확대에 따른 박리파괴. * : 보강효과는 각 시험체의 극한하중/ N 시험체의 극 한하중 ** : N 시험체의 항복 시의 처짐량에 대한 각 시험체 동등한 하중을 작용하였을 때의 처짐량을 비교한 값. Fig. 8. Fig. 11 Crack pattern for 50FP. FRP. Fig. 12 Crack pattern for 30FP. FRP . 50FP , SB 21%. 84% , 30FP . FRP. 27%. Fig. 13 Crack pattern for SB. . FRP 50FP 47%. , 30FP , SB. 26% 12% FRP box,. .. 50FP. 1.5 Fig. 14 Crack pattern for specimens. . 4.2 균열 및 파괴형태 Fig. 9 , 50FP. Fig. 12. . N. 30FP. N , SB. , .. Box. Fig. 15 Load-maxmum crack for specimens. plate Box core. skin interface. ,. 4.3 최적 Box형상 설계 Box core. .. FRP Plate. Vol. 4, No. 1, 2013. 43.

(5) Kwon, Min-Ho · Jung, Woo-Young · Spacone, Enrico. Sandwich Box .. 10kN FRP Plate 0.3488mm Box , core 3mm, 0.3502mm, 0.3488mm . FRP Plate Box. 10mm, 30mm 0.3512mm. 10mm 10mm. core 20mm core. .. Fig. 18 Modeling for FRP sandwich retrofited. , ,. 3. Displacement FRP Plate. . -. Fig. 16 Trend curve for displacement of sandwich box. 4mm ,. , FRP Plate FRP Sandwich Box ABAQUS. FRP Plate 22% .. . FRP Plate. Tabel 3. Results of test 재료 콘크리트 철근 FRP 우레탄 폼. 탄성계수 (MPa) 22,000 200,000 23,000 1.72. Poisson 비 0.18 0.3 0.2 0.1. . FRP Sandwich Box. -. FRP Sanewich Box 17%. . .. (a) Non-retrofited Fig. 17 Modeling for non-retrofited and FRP plate-retrofited. 44. J. Korean Soc. Adv. Comp. Struc.

(6) Shape Design and Performance Evaluation of FRP Box-type Stiffener For the Application of RC Structure. 5. 결 론 FRP. FRP Box .. 1) , . (b) FRP plate-retrofited. 2) FRP Plate. Box ,. FRP Box. core Plate Bottom Plate. FRP box. Top. . 3) , . 50FP +. (c) FRP sandwich box-retrofited. 30FP .. SB. Fig. 19 Analysis result. . 4) FRP Plate 22% FRP Plate . FRP Sandwich Box. -. (a) Non-retrofited. FRP Sanewich Box 17% FRP. .. , Box. FRP. core .. (b) FRP plate-retrofited. 감사의 글 이 논문은 2012년도 정부(교육과학기술부)의 재원 으로 한국연구재단의 지원을 받아 수행된 연구임. [No. 2012-0008762]. (c) FRP sandwich box-retrofited Fig. 20 Result of experiment and analysis. Vol. 4, No. 1, 2013. 45.

(7) Kwon, Min-Ho · Jung, Woo-Young · Spacone, Enrico. References Sim, J. S., Kim, G. S., Lee, S. M., and Kim, K. M. (1998). “A Experimental Study on the Flexural Characteristics of RC Beams Strengthened by GFRP.” Korea Concrete Institute Spring Research Meeting Collection Of Dissertations, pp. 559-565. Teng, J. G., Chen, J. F., Smith, S. T., and Lam, L. (2002). “FRP: strengthened RC structures.” FRP: Strengthened RC Structures, by JG Teng, JF Chen, ST Smith, L. Lam, pp. 266. ISBN 0-471-48706-6. Wiley-VCH, January 2002., 1. Yoo, S. W . and Bae, H. U. (2007). “Bond Slip Behavior Between Cast-In-Place Concrete and FRP Plank Used as Permanent Formwork and Tensile Reinforcement.” Korean Society of Civil Engineers Collection Of Dissertations, Vol. 27, No. 1A, pp. 69-77.. 46. J. Korean Soc. Adv. Comp. Struc.

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