소성힌지 영역의 접합부를 개선한 PC 구조벽체의 개발

강수민,오재근,김욱종,이도범,박홍근 한국지진공학회 2010 한국지진공학회논문집 Vol.14 No.2

PC(Precast Concrete) 구조시스템은 건식화 조립식 공법으로 구조물 건설에 있어 공기, 노동력 절감 등의 여러 장점을 가지고 있다. 하지만 구조벽체의 경우 이를 PC화하여 사용할 경우 접합부의 내진성능이 떨어지므로 PC 구조벽체를 사용하는 경우는 드물다고 할 수 있다. 본 연구에서는 이러한 점을 감안하여 접합부 성능을 개선하여 횡력저항요소로 사용가능한 2종류의 PC 구조벽체를 제안하였다. 제안된 PC 구조벽체는 RC 벽체 및 PC 벽체가 혼합된 복합 PC 벽체와 벽체하부 연결철근의 일부를 단면감소시키고 비부착상세를 적용한 PC 벽체로서 지진발생 시 충분한 강도와 변형능력을 확보할 수 있도록 하였다. 제안된 PC 구조벽체의 내진성능평가를 위하여 RC 벽체를 포함한 3가지 벽체에 대한 실험체를 제작하여 주기 횡하중 실험을 수행하였다. 실험결과, 제안된 PC 구조벽체는 강도, 강성, 변형능력 및 에너지 소산능력이 기존 PC 구조벽체보다 월등히 향상되어 우수한 내진성능을 확보할 수 있는 것으로 나타났다. The purpose of this study is to develop a precast concrete structural wall system that can assure reliable seismic performance. In previous studies, the connections of precast concrete structural walls have had some problems in their seismic performance. Therefore, this research proposes precast concrete structural walls which have an improved seismic performance. One is a hybrid precast concrete structural wall that is composed of a reinforced concrete component and a precast concrete component, and another is a precast concrete wall whose reinforcements have a partially reduced section and are partially unbonded from the surrounding concrete. To evaluate the seismic performance of the proposed precast concrete structural walls, the behavior of three specimens, including a reinforced concrete wall, were subjected to reversed cyclic combined flexure and shear. According to the test results, the proposed precast concrete structural walls have reliable seismic performance.

Seismic Performance of a New Type Concrete-Filled Precast Concrete Tubular Column

Chuang Du,Yanzhao Li,Chunxiao Zhang 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.2

To investigate the seismic behaviour of a new type of concrete-filled precast concrete tubular column, five concrete-filled precast concrete tubular columns varying in concrete strength and stirrup ratio were tested under cyclic loading. The behaviours of the failure mode, hysteretic curve, skeleton curve, bearing capacity, deformability, displacement ductility and energy dissipation were studied to evaluate the seismic resistance performance of the columns. The results show that the failure mode of the concrete-filled precast concrete tubular columns was flexural failure, and the hysteretic curve had a plump shuttle shape, which indicates that the concrete-filled precast concrete tubular column has good energy dissipating capacity. The bearing capacity of the specimen was increased with increasing concrete strength of the precast tube. The stirrup ratio has little effect on its bearing capacity, whereas it has a significant effect on the deformation, ductility and energy dissipation. The story drift of the specimens can meet the requirements of the elastic plastic story drift limit value of 1/50 of the code in China, and the ductility coefficient is greater than 3, which demonstrates that the concrete-filled precast concrete tubular column has excellent seismic properties.

프리캐스트 콘크리트 제품의 공장 인증 제도에 관한 연구

김형도,이상섭,박금성,배규웅 한국구조물진단유지관리공학회 2014 한국구조물진단유지관리공학회 논문집 Vol.18 No.6

1994년 성수대교 붕괴사고 이후 강구조물의 품질 관리를 위해 철강구조물제작공장 인증제도가 건설기술관리법에 도입되어 법정임의 인증제도로 운영되고 있다. 그러나 콘크리트 부재의 공장 생산 방식인 PC (Precast Concrete)에 대해 국가적인 품질인증 체계는 마련되어있지 않다. 이에 건축 구조용 PC를 대상으로 적절한 품질인증제도 도입을 위해 북미, 유럽, 일본 등의 PC 품질인증제도를 조사하였다. 북미에서 PC 공장인증제도를 운영하고 있는 곳은 PCI, NPCA, CPCI 등이 있다. 유럽에서 PC 제품을 판매하기 위해서는 CPR 305/2011을따르도록 법으로 정해져 PC 제품을 포함한 모든 건설 제품은 2013년 7월부터 CE 마크를 의무적으로 부착해야 한다. 일본의 경우 토목용PC 제품은 제품인증인 JIS 마크 인증을 받도록 되어 있고 건축 구조용 PC를 생산하는 공장은 일본 프리패브협회의 심사를 받고 있다. 이런 조사 결과에 근거하여 국내 인증 체계에 부합될 수 있도록 건축 구조용 PC 제품의 인증제도의 도입 방향을 이 논문에 제시하였다. The steel structure fabrication plant certification program was enacted as a part of the construction technology management act,article 24-3, to improve the quality of steel construction after the decay falling accident of Seongsu Bridge in 1994. However, thenational certification program for structural precast concrete that is a prefabricated construction products produced by casting concrete in plant is not implemented yet. So, to introduce the proper certification system for precast concrete, the quality certification programs of North America, Europe and Japan are surveyed. In North America, the organizations that manage the plant certification programs are PCI, NPCA, CPCI and so on. Sales of precast concrete elements in Europe are governed by theconstruction products regulation 305/2011. Therefore, CE marking is mandatory from July 2013 for all construction products including precast concrete. In Japan, precast concrete products used in civil engineering are certificated by JIS mark, product certification system and plants for manufacturing precast concrete building elements are audited by Japan Prefabricated Construction Suppliers and Manufacturers Association. Based on these survey studies, in this paper is described an adaptation of precast concrete plant certification to comport with the certification system in Korea.

Post-fire test of precast steel reinforced concrete stub columns under eccentric compression

Yong Yang,Yicong Xue,Yunlong Yu,Zhichao Gong 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.33 No.1

This paper presents an experimental work on the post-fire behavior of two kinds of innovative composite stub columns under eccentric compression. The partially precast steel reinforced concrete (PPSRC) column is composed of a precast outer-part cast using steel fiber reinforced reactive powder concrete (RPC) and a cast-in-place inner-part cast using conventional concrete. Based on the PPSRC column, the hollow precast steel reinforced concrete (HPSRC) column has a hollow column core. With the aim to investigate the post-fire performance of these composite columns, six stub column specimens, including three HPSRC stub columns and three PPSRC stub columns, were exposed to the ISO834 standard fire. Then, the cooling specimens and a control specimen unexposed to fire were eccentrically loaded to explore the residual capacity. The test parameters include the section shape, concrete strength of inner-part, eccentricity ratio and heating time. The test results indicated that the precast RPC shell could effectively confine the steel shape and longitudinal reinforcements after fire, and the PPSRC stub columns experienced lower core temperature in fire and exhibited higher post-fire residual strength as compared with the HPSRC stub columns due to the insulating effect of core concrete. The residual capacity increased with the increasing of inner concrete strength and with the decreasing of heating time and load eccentricity. Based on the test results, a FEA model was established to simulate the temperature field of test specimens, and the predicted results agreed well with the test results.

프리캐스트 콘크리트 제품의 공장 인증 제도에 관한 연구

김형도,이상섭,박금성,배규웅 한국구조물진단유지관리공학회 2014 한국구조물진단유지관리공학회 논문집 Vol.18 No.6

The steel structure fabrication plant certification program was enacted as a part of the construction technology management act,article 24-3, to improve the quality of steel construction after the decay falling accident of Seongsu Bridge in 1994. However, thenational certification program for structural precast concrete that is a prefabricated construction products produced by castingconcrete in plant is not implemented yet. So, to introduce the proper certification system for precast concrete, the qualitycertification programs of North America, Europe and Japan are surveyed. In North America, the organizations that manage theplant certification programs are PCI, NPCA, CPCI and so on. Sales of precast concrete elements in Europe are governed by theconstruction products regulation 305/2011. Therefore, CE marking is mandatory from July 2013 for all construction productsincluding precast concrete. In Japan, precast concrete products used in civil engineering are certificated by JIS mark, productcertification system and plants for manufacturing precast concrete building elements are audited by Japan Prefabricated ConstructionSuppliers and Manufacturers Association. Based on these survey studies, in this paper is described an adaptation of precast concreteplant certification to comport with the certification system in Korea. 1994년 성수대교 붕괴사고 이후 강구조물의 품질 관리를 위해 철강구조물제작공장 인증제도가 건설기술관리법에 도입되어 법정임의 인증제도로 운영되고 있다. 그러나 콘크리트 부재의 공장 생산 방식인 PC (Precast Concrete)에 대해 국가적인 품질인증 체계는 마련되어있지 않다. 이에 건축 구조용 PC를 대상으로 적절한 품질인증제도 도입을 위해 북미, 유럽, 일본 등의 PC 품질인증제도를 조사하였다. 북미에서 PC 공장인증제도를 운영하고 있는 곳은 PCI, NPCA, CPCI 등이 있다. 유럽에서 PC 제품을 판매하기 위해서는 CPR 305/2011을따르도록 법으로 정해져 PC 제품을 포함한 모든 건설 제품은 2013년 7월부터 CE 마크를 의무적으로 부착해야 한다. 일본의 경우 토목용PC 제품은 제품인증인 JIS 마크 인증을 받도록 되어 있고 건축 구조용 PC를 생산하는 공장은 일본 프리패브협회의 심사를 받고 있다. 이런 조사 결과에 근거하여 국내 인증 체계에 부합될 수 있도록 건축 구조용 PC 제품의 인증제도의 도입 방향을 이 논문에 제시하였다.

에폭시 콘크리트를 사용한 조립식 교량 상판 연결부의 피로거동에 과한 실험적 연구

成基泰,李丞鏞 충주대 산업과학기술연구소 2000 産業科學論文集 Vol.8 No.-

열화손상이 발생된 교량 상판의 보수를 위해서는 교통흐름의 지체, 대중의 불편함 및 경제적인 손실이 불가피하다. 그러므로, 교통량이 적은 시간대에 신속하게 교량 상판을 보수 또는 교체할 수 있는 공법의 적용이 바람직하다. 이러한 공법 중의 하나가 조립식 교량 상판을 현장에서 에폭시 콘크리트로 연결하는 방법이다. 따라서, 본 연구는 이 방법을 사용하였을 때 에폭시 콘크리트 연결부의 역학적 특성과 이상 유무를 파악할 목적으로 실험적 연구를 실시하였다. 그 결과, 조립식 교량 상판의 에폭시 콘크리트 연결부는 최대 설계활하중을 초과하는 반복하중이 작용하여도 충분한 피로강도를 갖고 있음을 알 수 있었다. 또한, 연결부 경계면의 분리나 철근 겹이음부의 미끄러짐은 나타나지 않아 조립식 상판 콘크리트와 에폭시 콘크리트는 일체로 거동함을 확인할 수 있었다. Rehabilitation of the deteriorated bridge decks causes travel delay, public inconvenience and economic loss. Therefore, it is desirable to adopt deck replacement techniques that allow repair work to be completed rapidly during the periods of low traffic volume. Precast deck method using epoxy concrete is satisfactory for that purpose. The experimental study is performed to investigate the mechanical behavior and safety of precast deck joints using epoxy concrete. The results show that epoxy concrete joints in precast deck have a sufficient fatigue strength under the cyclic load beyond maximum design live load. And the interface between epoxy concrete and precast concrete is not separated, so it is concluded that precast concrete and epoxy concrete behavior like one material.

Crack width control of precast deck loop joints for continuous steel-concrete composite girder bridges

Shim, Changsu,Lee, Chidong Techno-Press 2020 Advances in concrete construction Vol.10 No.1

Precast deck joints have larger crack width than cast-in-place concrete decks. The initial crack typically occurs at the maximum moment but cracks on precast joints are significant and lead to failure of the deck. The present crack equation is applied to cast-in-place decks, and requires correction to calculate the crack width of precast deck joints. This research aims to study the crack width correction equation of precast decks by performing static tests using high strength and normal strength concrete. Based on experimental results, the bending strength of the structural connections of the current precast deck is satisfied. However it is not suitable to calculate and control the crack width of precast loop connections using the current design equation. A crack width calculation equation is proposed for crack control of precast deck loop joints. Also included in this paper are recommendations to improve the crack control of loop connections.

In-Plane Quasi-Static Cyclic Tests on Emulative Precast Concrete Walls

Zhu Zhangfeng,Guo Zhengxing 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.8

This paper presents two types of emulative precast concrete walls with dry horizontal connection and semi-dry horizontalconnection. As for dry connection, vertical continuity reinforcing bars are grouted in metal bellows embedded in the precast wallpanel. As for semi-dry connection, the web reinforcing bars are still grouted in embedded metal bellows while the reinforcing barswithin boundary elements are overlapped and anchored in cast-in-place concrete. To assess the seismic performance of the twoconnections, three full-scale specimens, including one reference monolithic specimen and two precast specimens for eachconnection, were prefabricated and tested under in-plane quasi-static cyclic loading. The strength, stiffness, displacement ductility,and energy dissipation of the specimens were measured and compared. The experimental results demonstrated that, compared withthe monolithic specimen, both precast specimens exhibited satisfactory behavior and the semi-dry precast specimen performed betterthan the dry precast specimen in terms of ductility and energy dissipation. In addition, the analytical results showed that precastspecimens exhibited reliable seismic performance with high bearing capacity and large deformation capacity.

Shear behavior and shear capacity prediction of precast concrete-encased steel beams

Yunlong Yu,Yong Yang,Yicong Xue,Yaping Liu 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.36 No.3

A novel precast concrete-encased steel composite beam, which can be abbreviated as PCES beam, is introduced in this paper. In order to investigate the shear behavior of this PCES beam, a test of eight full-scale PCES beam specimens was carried out, in which the specimens were subjected to positive bending moment or negative bending moment, respectively. The factors which affected the shear behavior, such as the shear span-to-depth aspect ratio and the existence of concrete flange, were taken into account. During the test, the load-deflection curves of the test specimens were recorded, while the crack propagation patterns together with the failure patterns were observed as well. From the test results, it could be concluded that the tested PCES beams could all exhibit ductile shear behavior, and the innovative shear connectors between the precast concrete and cast-in-place concrete, namely the precast concrete transverse diaphragms, were verified to be effective. Then, based on the shear deformation compatibility, a theoretical model for predicting the shear capacity of the proposed PCES beams was put forward and verified to be valid with the good agreement of the shear capacities calculated using the proposed method and those from the experiments. Finally, in order to facilitate the preliminary design in practical applications, a simplified calculation method for predicting the shear capacity of the proposed PCES beams was also put forward and validated using available test results.

Quasi-static test of the precast-concrete pile foundation for railway bridge construction

Zhang, Xiyin,Chen, Xingchong,Wang, Yi,Ding, Mingbo,Lu, Jinhua,Ma, Huajun Techno-Press 2020 Advances in concrete construction Vol.10 No.1

Precast concrete elements in accelerated bridge construction (ABC) extends from superstructure to substructure, precast pile foundation has proven a benefit for regions with fragile ecological environment and adverse geological condition. There is still a lack of knowledge of the seismic behavior and performance of the precast pile foundation. In this study, a 1/8 scaled model of precast pile foundation with elevated cap is fabricated for quasi-static test. The failure mechanism and responses of the precast pile-soil interaction system are analyzed. It is shown that damage occurs primarily in precast pile-soil interaction system and the bridge pier keeps elastic state because of its relatively large cross-section designed for railways. The vulnerable part of the precast pile with elevated cap is located at the embedded section, but no plastic hinge forms along the pile depth under cyclic loading. Hysteretic curves show no significant strength degradation but obvious stiffness degradation throughout the loading process. The energy dissipation capacity of the precast pile-soil interaction system is discussed by using index of the equivalent viscous damping ratio. It can be found that the energy dissipation capacity decreases with the increase of loading displacement due to the unyielding pile reinforcements and potential pile uplift. It is expected to promote the use of precast pile foundation in accelerated bridge construction (ABC) of railways designed in seismic regions.