초록 ▼

· 고성능 재료기술을 반영한 프리캐스트 및 프리스트레스트 콘크리트 연구를 통해 성능 표준화 가이드라인과 설계기준 개발 및 예제집을 작성하였다.
1) 프리캐스트 복합화 공법에서 사용되는 프리캐스트 콘크리트와 현장타설 콘크리트 합성단면의 전단강도 평가 방법을 제안하였다.
2) PC접합부에 대한 독립적 설계기준의 근거 마련을 위해 PC접합부의 분류 방안을 제시하였고 변형기여분을 사용하여 PC접합부의 성능 평가 방안을 제시하였다.
3) 중공 PC부재 사용에 따른 건물의 응답 분석을 위한 부재 및 골조 거동에 대한 해석연구

· 고성능 재료기술을 반영한 프리캐스트 및 프리스트레스트 콘크리트 연구를 통해 성능 표준화 가이드라인과 설계기준 개발 및 예제집을 작성하였다.
1) 프리캐스트 복합화 공법에서 사용되는 프리캐스트 콘크리트와 현장타설 콘크리트 합성단면의 전단강도 평가 방법을 제안하였다.
2) PC접합부에 대한 독립적 설계기준의 근거 마련을 위해 PC접합부의 분류 방안을 제시하였고 변형기여분을 사용하여 PC접합부의 성능 평가 방안을 제시하였다.
3) 중공 PC부재 사용에 따른 건물의 응답 분석을 위한 부재 및 골조 거동에 대한 해석연구 및 PC 부재 연결을 위한 이음성능 실험과 중공 PC기둥의 압축 성능에 대한 실험을 수행하였고 중공 PC기둥을 활용한 건물의 시공 및 설계를 위한 설계법을 구축하였다.
4) 증기양생에 의한 강연선의 긴장력 손실을 실험 및 이론적 연구를 수행하여 새로운 긴장력 손실 모델을 개발하였다.
5) 국내 기술로 새로 개발된 2,160MPa급, 2,400MPa급 고강도 강연선과 고강도 강연선이 적용된 구조물의 성능 실험과 표준화 작업을 수행하였고 현 설계기준, KS 표준, 시방서를 검토하고 제개정안을 도출하였다.

Abstract ▼

Ⅲ. Research Program and Findings
In precast concrete construction, it is required that current design codes about precast systems, such as standardization of precast joint system and shear strength of composite members, should be reasonably investigated in accordance with the use of high-strength

Ⅲ. Research Program and Findings
In precast concrete construction, it is required that current design codes about precast systems, such as standardization of precast joint system and shear strength of composite members, should be reasonably investigated in accordance with the use of high-strength material. In additions, in prestressed concrete, relevant design codes should be examined and revised for the application of high-strength strands in structural members. Thus, the present research program focused on the following items.
1) PC and cast-in-place concrete composite members
2) Evaluation method for PC beam-column connection
3) PC frame system using hollowed PC columns
4) Prestressing loss of strands due to steam curing
5) Performance standardization and design code development of PSC structure using high-strength strand
1) PC and cast-in-place concrete composite members
The objective is that shear strength of composite members, PC and cast-in-place concrete, is defined to apply the composite construction site, and modified dapped end PCribbed slab is newly developed. In the former, the scope contains high-strength reinforcedconcrete, prestressed concrete, and steel fiber reinforced concrete in the PC members. In the latter, new PC slab system is economically designed compared to wet construction method, and also the structural performances of the system are verified to conduct simply supported or fixed end beam tests reflecting the every construction stages.
2) Evaluation method for PC beam-column connection
Evaluation method for PC beam-column connection was suggested according to the connection details and failure pattern. According to verify quantified performance of PC beam-column connection, displacement contribution of structural elements was used. The main classification categories are “monolithic connection” and “jointed connection”.
In order to suggest classification method and verification of structural behavior of various PC beam-column connection, structural testing for PC beam-column connection was carried out. Test was carried out with the same method which usually be used to verify the RC beam-column connections. Lateral force was loaded at the higher position of column and other elements was constrained with pin connection. For the verification of displacement contribution of each elements(2-beams, 2-columns and jointed area) 34-LVDTs were mounted at test specimens. As a result of test, each PC connection details have different displacement contribution ratio. According to the test results, monolithic connection can be classified to two categories, strong connection and ductile connection. The main difference of these connection detail is deformation of jointed area.
3) PC frame system using hollowed PC columns
The objective of this research is to develop the PC frame system using hollowed PC columns as an innovated system to improve the workability and structural capacity of PCsystem. The necessity of this research is based on the need of use of PC system in themanner of construction to overcome the problem caused by the lack of labor and low quality of engineers as well as especially on need of the improvement of workability and structural capacity. Also, to develop the improved system has been increasing due to the strengthened earthquake design code caused by the increase of seismic risk.
Analytical research about the behavior of PC columns and frame system with those was performed to analyze the response of building with hollowed PC columns as vertical elements. And an experiment was conducted to find tensile capacity of mechanical connection to connect PC elements each other. The compressive capacity of hollowed PC columns with various hollow size and reinforcement details was studied through experimental and analytical approach. From the research works, the behavior of hollowed PC column was verified corresponding to the construction procedure. Eventually, the design process was established to construct and design the building using hollowed PC column.
4) Prestressing loss of strands due to steam curing
When a tendon is subjected to high temperature during the steam curing process for the precast prestressed member, the loss of prestressing force occurs. The magnitude of its loss amounts to 5 to 19% of the initial prestressing force and thus can not be ignored in design. Although its loss was specified in some European codes, their predictions show inconsistent results. No provision is provided in domestic structural codes. In this study, experimental and theoretical investigations were conducted in order to identify the amount of prestress loss and the parameters affecting the prestress loss. A theoretical model was also developed to predict prestress loss during the steam curing. Its accuracy was validated by the comparison with the experimental results. Using the developed model and experimental resutls, a practical formula predicting the prestress loss was developded for engineers in practice and proposed for new code provision of the domestic codes.
In this study, both experiments and theoretical development of a model were performed. Experiments were: 1) pull-out test on prestressing strand at different equivalent ages in the condition of steam curing; and 2) re-tensioning tests on prismatic concrete member pretensioned with the strand. Based on the pull-out test results, empirical bond-slip model was developed. The remained prestress force was measured from the re-tensioning tests. The test results were used to validate the developed model and to identify the effects of different parameters on the prestress loss during the steam curing such as approximate increase in loss with respect to the maximum temperature during steam curing but the indifference of concrete compressive strength and initial prestressing.
The theoretical model was developed by reflecting the empirical bond-slip relationships between the strand and the concrete at elevated temperature during the steam curing. The model predicted that about 2.7 to 6.8% of prestress loss can occur. Based on the experimental results and parametric studies, a practical formula for the engineers in practice was developed and proposed as a new code provision.
5) Performance standardization and design code development of PSC structure using high-strength strands
First, this study performed uni-axial tensile tests to obtain data on the mechanical performances of the high-strength strands. Test results performed by the manufacturer of the strands were also collected. Collected data were used to standardize the mechanical performances and to establish the mathematical modelling of the stress-strain curves. The next step was the experiments on the performances of the prestressed members with the high-strength strands. Both of post-tensioned member and pre-tensioned member were considered in this study. The objective of the experiment on post-tensioned members was to verify the flexural performances, which include flexural strength, maximum displacement, crack pattern, crack spacing, crack width, failure mode, and yield of strand. On the other hand, the experiment on pre-tensioned members pursued the verification of the bond performances, which include transfer length and development length. The code provisions relevant to the behavior of the test specimens were carefully reviewed in terms of the suitability for the high-strengths strands. Together with the experiments, the necessity of the revision to the current code provisions was explored with analytical investigations.

목차 Contents

• 표지 ... 1
• 제출문 ... 2
• 보고서 요약서 ... 3
• 요약문 ... 4
• SUMMARY ... 9
• 목차 ... 14
• CONTENTS ... 17
• 제1장 연구개발과제 개요 ... 19
• 제1절 연구개발의 목적 및 필요성 ... 19
• 1. 연구 개발의 개요 ... 19
• 2. 연구 개발의 필요성 ... 20
• 제2절 연구개발의 정의, 범위, 특징 ... 23
• 제3절 관련분야의 국내외 기술개발 현황 ... 25
• 1. 국내 기술 및 산업 동향 ... 25
• 2. 국외 기술 및 산업 동향 ... 31
• 3. 특허 동향 ... 33
• 4. 종합 결론 ... 33
• 제4절 연구개발결과가 관련분야에서 차지하는 위치 ... 35
• 제2장 연구개발 수행 내용 및 결과 ... 36
• 제1절 프리캐스트 콘크리트와 현장타설 콘크리트 합성부재 ... 36
• 1. 연구배경 및 필요성 ... 36
• 2. 댑단부를 변형시킨 프리캐스트 리브 슬래브의 휨 성능 ... 37
• 3. 프리캐스트 콘크리트와 현장타설 콘크리트 합성보의 전단강도 ... 48
• 4. 프리스트레스 프리캐스트 콘크리트와 현장타설 콘크리트 합성보의 전단강도 ... 98
• 5. 강섬유보강 프리캐스트 콘크리트와 현장타설 콘크리트 합성보의 전단강도 ... 133
• 6. 연구수행 결과 ... 151
• 제2절 프리캐스트 콘크리트 접합부의 분류 ... 153
• 1. 연구수행 전략 및 방법론 ... 153
• 2. 연구수행 과정 및 내용 ... 156
• 3. 연구수행 결과 ... 172
• 제3절 중공 PC기둥과 이를 이용한 프리캐스트 콘크리트 골조구조 ... 175
• 1. 연구수행 전략 및 방법론 ... 175
• 2. 연구수행 과정 및 내용 ... 176
• 3. 연구수행 결과 ... 211
• 제4절 증기양생에 따른 프리스트레스 손실 ... 212
• 1. 연구수행 전략 및 방법론 ... 212
• 2. 연구수행 과정 및 내용 ... 212
• 3. 연구수행 결과 ... 268
• 제5절 고강도 강연선 적용 PSC 구조물의 성능표준화 및 설계기준 개발 ... 270
• 1. 연구수행 전략 및 방법론 ... 270
• 2. 연구수행 과정 및 내용 ... 271
• 3. 연구수행 결과 ... 367
• 제3장 최종 연구성과 및 적용실적 ... 368
• 제1절 핵심연구성과 ... 368
• 1. 고성능 재료적용 구조물의 성능 표준화 가이드라인 ... 369
• 2. 고성능 재료적용 구조물의 설계기준 개발 ... 375
• 3. 고성능 재료적용 구조물의 설계기준 관련 예제집 작성 ... 426
• 제2절 학술 성과 ... 455
• 1. SCI급 논문 실적 ... 455
• 2. 학술지 논문 실적 ... 456
• 3. 학술대회발표 실적(국외) ... 457
• 4. 학술대회발표 실적(국내) ... 458
• 제4장 연구목표 달성 및 효과 ... 462
• 제1절 연구개발 최종목표 ... 462
• 제2절 성과목표 및 성과지표의 달성도 ... 463
• 제3절 연구개발 성과의 효과 분석 ... 468
• 제5장 연구성과의 활용 및 추가연구 필요성 ... 476
• 제1절 연구성과 향후 활용방안 ... 476
• 제2절 추가연구 필요성 ... 478
• 참고문헌 ... 480
• 끝페이지 ... 488