초록 ▼

코핑부의 주형 매립형 거더교량 기술 개발
◦ 시공 프로세스 및 접속부/접합부 상세구조 구체화
◦ 강결구조 연속교 및 단차 코핑부를 갖는 교각, 주형과 단차 코핑부 강결 접합부 개발
◦ 단차 코핑부와 철근콘크리트 슬래브와의 접속부에 대한 철근보강방법 구체화
코핑부의 주형 매립형 거더교량 성능검증을 통한 설계 시공 기술 개발
◦ 제안교량의 PS강봉, 정착구, 기둥, 온도 등 구조적 특성을 고려한 상세해석
◦ 구조성능 개선상세에 대한 부모멘트 구조성능 검증시험
◦ 제안교량 실용화 타당성 조사 및 실물

코핑부의 주형 매립형 거더교량 기술 개발
◦ 시공 프로세스 및 접속부/접합부 상세구조 구체화
◦ 강결구조 연속교 및 단차 코핑부를 갖는 교각, 주형과 단차 코핑부 강결 접합부 개발
◦ 단차 코핑부와 철근콘크리트 슬래브와의 접속부에 대한 철근보강방법 구체화
코핑부의 주형 매립형 거더교량 성능검증을 통한 설계 시공 기술 개발
◦ 제안교량의 PS강봉, 정착구, 기둥, 온도 등 구조적 특성을 고려한 상세해석
◦ 구조성능 개선상세에 대한 부모멘트 구조성능 검증시험
◦ 제안교량 실용화 타당성 조사 및 실물교량 건설을 위한 대상교량 조사/선정
코핑부의 주형 매립형 거더교량 실용화 사업화 기술개발
◦ 동적거동 수치해석 및 실물교량 계측실험 결과와 동일조건 구조해석 결과 비교검토
◦ 구조성능 개선상세에 대한 피로 및 내진성능 검증시험
◦ 잔류응력 검토 및 구조상세 용접방안 제시
◦ 제안교량 시공 프로세스 및 시공상세 개발 및 시공 및 유지관리 가이드라인 개발
◦ 실물교량 정⋅동적 계측실험을 통한 내하력 평가 및 구조적 안전성 검증
◦ 제안교량 구조형식의 LCC분석 및 선행기술조사, 원가분석, 건설신기술 신청

Abstract ▼

Study on Practicality of Steel I-girders to Inverted-T Bent Cap

Currently, general girder bridges intrude into the space under the bridge due to its blunt side shape caused by pier coping, bridge bearing, and girder height, reducing the visual openness as well as making maintenance such as br

Study on Practicality of Steel I-girders to Inverted-T Bent Cap

Currently, general girder bridges intrude into the space under the bridge due to its blunt side shape caused by pier coping, bridge bearing, and girder height, reducing the visual openness as well as making maintenance such as bridge bearing replacement difficult. The technology proposed in this research and development is a construction method that installs the coping, which was installed previously at the upper end of the pier column, at a height of the main girder to integrate the coping and girder using a PS bar and make them rigid. It can minimize the number of bridge bearings thereby reducing construction costs and improving aesthetic view by ensuring the feeling of special openness. It is also expected to improve seismic performance due to the rigidity of joints between coping and girder.

The result of the research and development can be summarized as follows:

For the basic design of steel I-girders to inverted-T bent cap, foreign case studies were investigated and inverted T-shaped coping, which had high structural stability in negative-moment tension parts, was selected as the target bridge type. In addition, the final draft included the analysis result on joint method between the main girder and the pier coping.

The analysis on economic feasibility showed that the construction cost per steel I-girder to inverted-T bent cap was KRW 33 million, which was about 61% of the existing bridge construction cost. This cost is a direct cost so if other overhead expenses are considered, economic feasibility will be improved further.

For the overall system analysis on steel I-girders to inverted-T bent cap, the appropriate number of spans (continuous 6 spans) was derived considering thermal load, and appropriate cross-section against internal force at a section was identified by examining pier columns. The overall system analysis was conducted to verify the performance through tests on test specimen joints and detailed structuralanalysis. A test specimen was fabricated by selecting a 52 m-long 2-span continuous bridge to analyze the measurement results. The analysis results were compared and analyzed with numerical analysis results using ABAQUS. The test result showed that a method of connecting joints and main girder by prestressing the PS steel rod showed an integrated behavior since relative displacement at the joint did not occur while applying the service load.

The fatigue test and static load test were conducted as follows. Steel bridge joints of steel I-girders to inverted-T bent cap was fabricated to full-scale based on the load test and analysis result of previous studies and the fatigue test was conducted with a parameter indicating whether prestressing was used or not. The static load test was also conducted to analyze the fracture behavior after the fatigue test. The relative displacements of both specimens did not increase significantly in the fatigue test up to 2,000,000 repeated loads but the relative displacement of specimen where prestressing was not used increased rapidly around 600 kN in the static load test. That is, although both of the specimens were safe within the fatigue stress range, the prestressing improvement effect on usability in regard to deflection and crack was clearly observed.

The level of effect on residual stress in the welded part of the proposed bridge was similar with that in general plate girders. The analysis on the maximum displacement and residual stress distribution at PS bar joints indicated that they were not greater than those of general girders. The numerical analysis on dynamic behavior specifies that the maximum allowable vertical deflection of the proposed bridge was L/800, which is 37.5 mm (Design criteria for railroad, 2013). The maximum deflection was 17.9 mm at the time a standard truck load was applied, which was analyzed as safe.

The load carrying capacity of full-scale bridges was divided as follows: deflection due to concrete pouring at the deck slab, strain measurement, and static and dynamic behavior of bridges due to vehicle load before bridge open. Currently, a bridge that applied the proposed technology is still under construction so performance will be verified once the bridge is complete. In the design guideline, a design method of coping and joints was proposed and in the construction guideline, manufacturing and construction methods were proposed. In the maintenance guideline, management plan and order were proposed.

For practicality and commercialization, memorandums of understanding were signed with local companies in Cambodia and Vietnam, and the commercialization of the study results is under way. A field application in Korea was conducted with Budong Bridge located in Budongcheon, which is part of the flood control project in the water system of Tamjin River. In addition, promotional activities such as not only participation in technical exhibition through Civil Expo and Land, Infrastructure and Transport Technology Fair but also production and distribution of advertisement brochures, have been underway continuously. The activities for academic verification of this study were also conducted to publish three journals in Korea, two foreign journals (SCI level), nine conference papers in Korea, and six conference papers in foreign nations. The activities for commercialization were also conducted: five applications for patent and three registered patents. Furthermore, registration of two programs, standardization by girder span, guidelines of design, construction, and maintenance, LSD design guideline, design automation guideline, and BIM design guideline were developed and technical execution contracts were signed.

The proposed technology integrated a pier coping part with a pier by placing a coping inside the girder to reduce bridge height and alleviate the vertical grade of the overpass. It is highly efficient in minimizing construction cost because of the slimness of the bridge, reducing the replacement cost of a bridge bearing during the maintenance phase, improving vehicle drivability, and ensuring economic feasibility directly and indirectly. The proposed technology will advance the development of green growth policy and CO₂ reduction construction technology. It is advantageous not only in terms of quality and technology compared to products from local and oversea competitors but also in terms of price. It has also fewer limitations on construction time, which can expanse the application scope further. As successful application of the proposed technology has been proven through field applications in South Korea, it will be utilized in oversea markets gradually. To achieve this, various data about sufficient application achievements and performance evaluation after use will be collected and related source technology will be developed in the future.