볼트 체결형 강판-콘크리트 합성보의 형상 제안

조태구(Tae-Gu Cho),최병정(Byong-Jeong Choi) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.7

강판 콘크리트 합성보는 강판, 콘크리트 및 2가지의 이질 재료를 결합시키는 전단 연결재로 구성되어 있다. 일반적으로 강판은 기존의 합성보에 용접하여 조립된다. 본 연구에서는 전단 연결재를 감소시키고, 작업성을 향상시키기 위해 SPC (Steel Plate Concrete Composite Beam) 보라 불리는 새로운 강판 콘크리트 합성보를 개발했다. SPC 보는 전단 연결재 없이 절곡된 강판과 콘크리트로 구성된다. 절곡된 강판은 용접 대신 고강도 볼트로 조립된다. 또한, 건설 현장에서 작업성을 향상시키기 위해 슬래브와 접합부에 모자 모양의 Cap이 부착된다. 변위 제어 모드에서 2점 가력 실험을 수행하였고, 시편의 휨 강도를 계산하기 위해 소성 응력 분포법과 변형률 적합법을 사용하였다. 시험 결과에 따르면 새로운 SPC 보의 휨 강도는 완전 합성보 강도의 76 %의 값이 나왔다. Cap은 스터드와 부속 철물의 역할을 수행한다. 또한, Cap의 간격 제어를 통해 합성율의 증가가 가능하고, SPC 합성보의 합성율을 고려할 경우 변형률 적합법을 통해 SPC 합성보의 휨 성능 평가가 가능하다. The steel-plate concrete composite beam is composed of a steel plate, concrete and a shear connector to combine the two inhomogeneous materials. In general, the steel plate is assembled by welding an existing composite beam. In this study, a new steel-plate concrete composite (SPCC) beam was developed to reduce the size of the shear connector and improve its workability. The SPCC beam was composed of folded steel plates and concrete, without any shear connector. The folded steel plate was assembled with high strength bolts instead of welding. To improve the workability in field construction, a hat-shaped cap was attached in the junction with the slab. Monotonic two-point load testing was conducted under displacement control mode. The flexural strength of the SPCC beam specimen was calculated to be 76% of that of the complete composite beam by using the plastic stress distribution method and strain compatibility method. The cap acted as the stud and accessory. The synthesis rate could be increased by controlling the gap of the cap, and the bending performance could be evaluated by using the strain fitting method considering the synthesis rate of the SPCC beam.

편심재하된 하이브리드 FRP-콘크리트 합성 기둥의 구조적 특성

Choi, Jin-Woo,Seo, Su-Hong,Park, Joon-Soek,Joo, Hyung-Joong,Yoon, Soon-Jong 한국복합신소재구조학회 2013 복합신소재구조학회논문집 Vol.4 No.4

Pile foundations constructed by the fiber reinforced polymer plastic piles have been used in coastal and oceanic regions in many countries. Generally, fiber reinforced polymer plastic piles are consisted of filament winding FRP which is used to wrap the outside of concrete pile to increase the axial load carrying capacity or pultruded FRP which is located in the core concrete to resist the bending moment arising due to eccentric loading. In this paper, the analytical procedures of hybrid concrete filled FRP tube flexural members are suggested based on the CFT design method. Moreover, the analytical results are compared with the experimental results to obtained by the previous researches. The results of comparison analyses are performed to estimate the accuracy of the analytical procedure for hybrid FRP-concrete composite compression test, members under eccentrical loading.

편심재하된 하이브리드 FRP-콘크리트 합성 기둥의 구조적 특성

최진우 ( Jin Woo Choi ),서수홍 ( Su Hong Seo ),박준석 ( Joon Soek Park ),주형중 ( Hyung Joong Joo ),윤순종 ( Soon Jong Yoon ) 한국복합신소재구조학회 2013 복합신소재학회논문집 Vol.4 No.4

Pile foundations constructed by the fiber reinforced polymer plastic piles have been used in coastal and oceanic regions in many countries. Generally, fiber reinforced polymer plastic piles are consisted of filament winding FRP which is used to wrap the outside of concrete pile to increase the axial load carrying capacity or pultruded FRP which is located in the core concrete to resist the bending moment arising due to eccentric loading. In this paper, the analytical procedures of hybrid concrete filled FRP tube flexural members are suggested based on the CFT design method. Moreover, the analytical results are compared with the experimental results to obtained by the previous researches. The results of comparison analyses are performed to estimate the accuracy of the analytical procedure for hybrid FRP-concrete composite compression test, members under eccentrical loading.

An Improved Analysis Model for the Ultimate Behavior of Unbonded Prestressed Concrete

조태준,김명한 한국공간구조학회 2017 한국공간구조학회지 Vol.17 No.4

An innovative analysis method is proposed in this paper for the determination of ultimate resistance of prestressed concrete beams. The proposed method can be applied to simply supported or continuous beams in a unified manner whether structure and external loads are symmetric or not. Through the iterative nonlinear strain compatibility solutions, this method can also be applied to the non-prismatic section/un-symmetrical composite structures under moving load. The conventional studies have used the failure criteria when the strain of concrete reaches 0.003. However compared with bonded case, the value of strain in the reinforcement is much smaller than bonded case, thus, unbonded prestressed cases show compressive failure mode. It is shown that the proposed method gives acceptable results within 5% error compared with the prior experimental results. It can be shown that the proposed method can reach the solution much faster than typical three-dimensional finite element analysis for the same problem. This method is applicable to the existing unbonded prestressed members where deterioration has occurred leading to the reduced ultimate resistance or safety. In all, the proposed procedure can be applied to the design and analysis of newly constructed structures, as well as the risk assessment of rehabilitated structures.

An Improved Analysis Model for the Ultimate Behavior of Unbonded Prestressed Concrete

조태준,김명한,Cho, Taejun,Kim, Myeong-Han Korean Association for Spatial Structures 2017 한국공간구조논문집 Vol.17 No.4

An innovative analysis method is proposed in this paper for the determination of ultimate resistance of prestressed concrete beams. The proposed method can be applied to simply supported or continuous beams in a unified manner whether structure and external loads are symmetric or not. Through the iterative nonlinear strain compatibility solutions, this method can also be applied to the non-prismatic section/un-symmetrical composite structures under moving load. The conventional studies have used the failure criteria when the strain of concrete reaches 0.003. However compared with bonded case, the value of strain in the reinforcement is much smaller than bonded case, thus, unbonded prestressed cases show compressive failure mode. It is shown that the proposed method gives acceptable results within 5% error compared with the prior experimental results. It can be shown that the proposed method can reach the solution much faster than typical three-dimensional finite element analysis for the same problem. This method is applicable to the existing unbonded prestressed members where deterioration has occurred leading to the reduced ultimate resistance or safety. In all, the proposed procedure can be applied to the design and analysis of newly constructed structures, as well as the risk assessment of rehabilitated structures.

변형거동을 고려한 지오스트립 보강재의 장기성능 평가

전한용,정연인,Jeon, Han-Yong,Chung, Youn-In 한국섬유공학회 2006 한국섬유공학회지 Vol.43 No.4

Strain compatibility was applied to examine the limit of long-term allowable strength determination for geostrip as geosynthetic reinforcement. Creep test was performed for geostrip reinforcements according to SIM(step isothermal method) to obtain isochronous curve. Through the isochronous curve of geostrip reinforcements, the long-term allowable tensile properties of geostrip reinforcements was interpreted and analyzed.

Experimental and analytical investigation of composite columns made of high strength steel and high strength concrete

Binglin Lai,J.Y. Richard Liew,Mingxiang Xiong 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.33 No.1

Composite columns made of high strength materials have been used in high-rise construction owing to its excellent structural performance resulting in smaller cross-sectional sizes. However, due to the limited understanding of its structural response, current design codes do not allow the use of high strength materials beyond a certain strength limit. This paper reports additional test data, analytical and numerical studies leading to a new design method to predict the ultimate resistance of composite columns made of high strength steel and high strength concrete. Based on previous study on high strength concrete filled steel tubular members and ongoing work on high strength concrete encased steel columns, this paper provides new findings and presents the feasibility of using high strength steel and high strength concrete for general double symmetric composite columns. A nonlinear finite element model has been developed to capture the composite beam-column behavior. The Eurocode 4 approach of designing composite columns is examined by comparing the test data with results obtained from code's predictions and finite element analysis, from which the validities of the concrete confinement effect and plastic design method are discussed. Eurocode 4 method is found to overestimate the resistance of concrete encased composite columns when ultra-high strength steel is used. Finally, a strain compatibility method is proposed as a modification of existing Eurocode 4 method to give reasonable prediction of the ultimate strength of concrete encased beam-columns with steel strength up to 900 MPa and concrete strength up to 100 MPa.

식재기반을 담는 RDT 거더교의 구조성능 검증

하태열(Ha, Tae-Yul),한종욱(Han, Jong-Wook),양인욱(Yang, In-Wook) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.3

RDT(Reversed Double T) 거더교는 생태교 맞춤형으로 개발된 PSC 교량 형식이다. 모음 ㅛ형상과 유사한 단면형상 이 가장 큰 특징이며 거더 내부 공간에 흙을 담을 수 있어 상부 구조 전체 높이를 획기적으로 낮추고 시공성과 경제성이 우수하여 생태교로써 적용이 활발할 것으로 기대되는 공법이다. 새로 제안된 RDT 거더교의 실적용을 위해서는 공용 중 안전 성 검증이 필요하다. 본 연구에서는 RDT 거더교의 실물모형 실험체를 설계 및 제작하여 정적재하 실험을 수행하였다. 실험 결과와 변형률적합법을 이용한 비선형 해석 결과를 바탕으로 거동을 평가하고 구조성능을 검토하였다. 검토 결과, RDT 거더 교는 사용하중의 2배 이상 균열 안전성을 확보하고 있으며 우수한 휨 성능을 보유하고 있는 것으로 나타났다.

정현파형 주름웨브 보를 적용한 합성보의 휨거동 및 설계

김대경(Kim, Dae Kyung) 한국강구조학회 2023 韓國鋼構造學會 論文集 Vol.35 No.3

중공형 콘크리트 충전 FRP Tube 말뚝의 휨강도 산정

김형준,정흥진 한국구조물진단유지관리공학회 2022 한국구조물진단유지관리공학회 논문집 Vol.26 No.6

본 연구에서는 복합말뚝의 장점을 활용하고 CFT말뚝의 단점인 부식에 대한 문제점을 해결할 수 있는 모델로 중공형 콘크리트 충전FRP Tube 말뚝(Hollow Concrete Filled FRP Tube Pile, HCFFT말뚝)을 제시하였고, 수치해석 모델을 개발하여 거동을 분석하였다. 콘크리트가손상 소성 거동, 강재가 항복 소성 거동, FRP가 탄성 거동을 한다는 것을 고려하여 변형률적합법을 적용하고, 중립축으로부터의 거리에 따른FRP Tube 단면의 변화를 고려하여 HCFFT말뚝의 휨 강도 산정식을 제안하였다. 휨 강도 산정식과 수치해석 결과, 실험결과를 비교 분석하여적정성을 검증하였다. 본 연구 결과는 FRP를 이용한 다양한 HCFFT말뚝의 최적설계에 기초자료로서 활용될 수 있을 것으로 판단된다. In this study, Hollow Concrete Filled FRP Tube Pile(HCFFT Pile) was proposed as a model to utilize the advantages of composite piles andsolve the problem of corrosion, which is a disadvantage of CFT piles, and a numerical analysis model was developed to analyze their behavior. The straincompatibility method was applied considering the damage plastic behavior of concrete, the yield plastic behavior of steel, and the elastic behavior ofFRP. The flexural strength calculation equation of HCFFT piles was proposed considering the change of the FRP tube section according to the distancefrom the neutral axis. The flexural strength calculation equation, numerical analysis results, and experimental results were compared and analyzedto verify their adequacy. The results of this study can be used as basic data for the optimal design of various HCFFT piles using FRP.