Recently, the use of transfer slab system has increased greatly. However, several construction problems are being encountered owing to its excessive thickness. Therefore, in this study, a transfer slab system that uses a reverse drop panel, which can utilize the facility space of the pit floor by reducing the transfer slab thickness, was considered. To investigate the shear behavior of transfer slab system that uses the reverse drop panel, the two-way shear strength of transfer slab-column connection with the reverse drop panel was analyzed using nonlinear FE analysis. In addition, the two-way shear strength evaluations of transfer slab with the reverse drop panel conducted using the existing evaluation methods were verified by comparing the strengths predicted by those methods with the results of nonlinear FE analysis.

최근 국내에서는 고층 벽식 아파트 건설 시, 하부 주차공간과 공용공간 확보를 위하여 RC 전이슬래브 시스템을 사용하는 경우가 증가하고 있다. 하지만 두께가 얇은 RC 무량판 슬래브를 위해 개발된 설계방법 및 구조성능평가 방법을 두께가 매우 두꺼운 전이슬래브 구조설계에 그대로 사용하고 있다는 문제점이 있다. 따라서 합리적인 전이슬래브의 구조설계를 위해서는 RC 전이슬래브 시스템의 2면 전단거동 양상에 대한 명확한 분석이 필요하다. 이에 따라 본 연구에서는 전이슬래브의 두께, 콘크리트 강도, 전단경간비, 철근비 등 다양한 설계변수에 따라 비선형 FEM을 이용하여 전이슬래브의 2면 전단거동을 분석 하였다. 또한 비선형 FEM 해석결과와 기존의 2면 전단강도 평가식으로 예측한 전단강도를 비교분석하여 기존 평가식의 전이슬래브 2면 전단강도 평가 유효성을 검토하였다.

건물외피 발생하는 열교현상은 건물의 단열성능 및 외피의 내구성에 영향을 미치며, 국내의 일반적인 주거형식인 공동주택의 발코니에 있어서 이러한 열교현상은 중요하게 고려되고 있다. 이와 같이 내·외부 발코니 슬래브 사이에서 발생하는 열교현상을 최소화하기 위한 목적으로 열교차단장치가 개발되었으며 다수의 건설현장에서 적용되고 있다. 철근콘크리트 슬래브 벽-슬래브 접합부에 열교차단장치를 적용함으로써 건물의 단열성능을 향상될 수 있으나 풍하중과 같은 양방향의 하중에 의해 열교차단장치 삽입부위가 적합한 구조성능을 확보하고 있는지에 대한 검증이 요구된다. 따라서 본 연구에서는 철근콘크리트 슬래브에 적용된 열교차단장치의 구조성능을 확인하기 위해 변위제어 방식으로 30 싸이클의 반복하중을 가력하였다. 열교차단장치가 삽입된 접합부는 요구되는 구조성능을 확보하며, 최대 모멘트강도, 에너지소산능력, 연성비가 기존의 철근콘크리트 슬래브와 비교하여 향상되는 것으로 나타났다.

Main topics in this study is a new structural detail for connection between H-Steel or SRC column and flat plate slab. We carried out to evaluate the punching shear performance of H-steel or SRC column + RC slab system for vertical load and lateral load. From the test results structural characteristics - yield moment, yield rotation, maximum moment, deformation capabilities ect. - are obtained and evaluated. In this paper as a shear reinforcement for supporting region of plate closed stirrup type and shear band are used, and their test results are compared.

An experimental study was carried out to evaluate the punching shear performance of H-steel column + RC slab system for vertical load. Three specimens were constructed for interior column-slab system. All specimens were the same configuration and material properties except for columns such as RC column+flat plate slab and H-Steel column+flat plate slab. From the test results structural characteristics (maximum proof stress, maximum displacement, deformation capabilities and so on) are obtained and evaluated.

The flat plate slab system have many good features, which are design flexibilities, saving of story-height and economy of construction etc. But the study of flat plate slab system for H-steel column have been rare both at home and abroad. Recently high-rise residential and commercial buildings have been constructed in urban areas in Korea. The suggested dowel connection system is more likely to adoptable because it remarkably contribute to save inter story height and also to have many advantages compared with conventional steel works such as H-Steel frame + Deck plate slab system. This study aims at developing design method and program for connection between H-Steel column and flat plate slab system, which contribute to save significantly inter-story height.

Recently, earthquakes occur over 30 times a year in Korea. In addition, earthquakes originating from the neighborhood countries were sensed in Korea and caused serious human casualties and economic loss. In Japan, U.S.A., New Zealand and etc., forces seismic design of building structures to prevent seismic damage. In Korea, seismic design has been applied to building structures with a scale larger than defined in the building code since 1988. However, serious seismic damages are expected for wall-type apartment buildings, which were designed before 1988 without application of seismic design. Therefore, appropriate seismic retrofitting methods that are economical and easy to construct are required for such buildings. In this study, seismic retrofitting methods using steel plates or sections are developed for the wall-type apartment buildings. Proposed retrofitting methods improve lateral stiffness of the wall-slab system without excessive increment of loads on base structure. The effect of retrofitting using plates, T-sections and H-sections was examined experimentally for wall-slap system test models. In the experiment, the performance of the joint and slab of the test models was improved and the retrofitting effect was proved to be excellent.

The reinforced concrete wall type apartments built before 1988 in Korea, which are rarely seen in other countries, were constructed using tunnel form method for convenience of construction. Tunnel form method, however, do not arrange bearing walls in the direction of long side of the apartment, and this results in little resistance capability against lateral loads in that direction. Consequently, there exists significant collapse possibility due to the formation of plastic hinge at the joints of wall and slab during earthquake. This study experimentally investigates the reinforcement methods using carbon sheet and L-shaped steel which were not seismically designed. The reinforcement method using carbon sheet and L-shaped angle, has following advantages; construction workability, usage of light-weight material, and little requirement for the installation room. The specimen with steel bar fill up using modified epoxy mortar in the mid-span of the slab shows the same stiffness as the standard specimen without reinforcement and the stiffness of the specimen reinforced by carbon sheets without L-shaped steel was increased by only about 13%, implying that those existing methods cannot provide significant reinforcement effects. For the specimens of which wall-slab joints were reinforced using both carbon sheet and L-shaped steel, the increase of stiffness ranges from 43% to 496% and the increase of energy dissipation amount ranges from 120% to 233%. Also it was identified that the linkage method using penetration bolts was more efficient than the one using expansion anchors in increasing stiffness, strength and energy dissipation capacity.

Earthquake resistant design was introduced to Korea in 1988 for tall buildings, in 1992 for highway bridges and even earlier than that for nuclear power plants. The apartments designed by large unit housing planning was constructed by tunnel form method for the construction convenient in 1980. As a results, many structures without any seismic resistance capacity were built during the 80’s. In this paper, to improve the seismic capacity in wall-slab joint, experiments which improve and retrofit a seismic capacity by steel reinforcing, unequal angle bracing, carbon sheet attachment are carried out. These methods also are economic and simple in mitigating seismic hazard, improving earthquake-resistance performance, and reducing the risk level of building occupants. Consequently these methods were confirmed its effectiveness in improving the seismic performance were confirmed its effectiveness.

Recently the construction of residential building faces many difficulties due to the shortage of building materials and works. Simplifying the stage of processing and assembling reinforcing rods and increasing the efficiency of them in reinforced concrete construction can be used to settle the difficulties. In the respect, structural wire-fabric is utilized. The purpose of this study, instead of deformed steel bars, to examine the utilization of slab joint, which is accompanied with a large deformation in the structure subjected to seismic loads, to suggest reinforcing method which is efficient, easily constructible and structurally safe. The results are as follows ; 1. The ductility capacity of slab reinforced by welded wire fabric was less than with deformed bar in discontinuous slab joint. To enhance the ductility capacity, deformed bar should be used with welded wire fabric for the longitudinal reinforcement. 2. It is avoid to use loop welded wire fabric as the longitudinal reinforcement in wall, because the strength and ductility capacity showed lower value than that with deformed bar. 3. Using welded wire fabric in wall structures, it need deformed bar reinforcement with sufficient anchorage length.

Recently the construction of residential building faces many difficulties due to the shortage of building materials and works. Simplifying the stage of processing and assembling reinforcing rods and increasing the efficiency of them in reinforced concrete construction can be used to settle the difficulties. In the respect, structural wire-fabric is utilized. The purpose of this study, instead of deformed steel bars, to examine the utilization of slab joint, which is accompanied with a large deformation in the structure subjected to seismic loads, to suggest reinforcing method which is efficient, easily constructible and structurally safe. The results are as follows ; 1. The ductility capacity of continuous slab joints reinforced by welded wire fabric is less than that with deformed bar. But continuous slab joint is reinforced by deformed bar for the longitudinal reinforcement, it is increase strength and ductility capacity. 2. It is recommended that simple cut jointing of welded wire fabric should be avoided in wall-wall joints.

In this study, an experimental research was conducted to investigate the effective compressive strengths of slab-column connections with different strengths. From the test results, it was found that the effective compressive strengths of the interior columns completely restrained by slab were similar to the compressive strengths of the columns.

Finite element analysis is conducted for investigation of structure behavior of high strength concrete(HSC) column-normal strength concrete(NSC) slab connection according to aspect ratio(h/c). Analysis method is verified through comparison of experiment and analysis. As a result, regarding to the aspect ratio, the ultimate strength of column-slab connection decreased as the column dimension increased while the slab thickness did not influence on the ultimate strength of the connection.

In this paper, the seismic performance of existing column-tree connections using composite deck plate was experimentally evaluated. As a result, although two specimens were not founded the brittle fracture at the beam-to-column, composite slab were destroyed by crushing at the beam-to-column connection.

In this study, rational prediction models for the effective compressive strengths of HSC corner and interior columns with intervening NSC slabs are developed. A structural analogy between HSC column-NSC slab joint and brick masonry is used to develop the prediction models. In addition, the aspect ratio of slab thickness to column dimension and the surrounding slab confinement effect are considered in the models. The proposed prediction model is verified by comparison with experimental results and various prediction expressions. As a result, with average test-to-predicted ratios of 1.00 for HSC corner columns and 1.09 for interior columns, the proposed equation provides superior predictions over all of the existing effective strength prediction approaches including KCI structural concrete design code(2012).

In this study, an experimental study to investigate the shear friction behavior of the SC Wall to RC slab connection was carried out. The maximum shear friction capacity and failure mode were examined, and the results were also compared with theoretical value. Finally, the results are to be used for the basic reference of the design guideline(draft) for the RC-SC connection.

In this study, experimental research was carried out to study the structural performance of slab-column joints designed by the application of reducing of joint regions damage using steel fiber reinforced concrete. Test results showed that specimens(RCFPS series) were increased the maximum load-carrying capacity by 1.12~1.23 times and showed stable hysteresis behavior in comparison with the standard specimen(SRCFP).

최근 건설공사의 공기단축을 위하여 프리캐스트 콘크리트(Precast Concrete)에 대한 관심이 점차 증가하는 추세이다. 본 연구에서는 프리캐스트 콘크리트 중 내부에 중공을 설치하여 중량을 감소시킨 할로우코어 슬래브 간의 접합부 전단성능 평가에 대한 실험적 연구를 수행하였다. 실험의 주요 변수는 할로우코어 슬래브 상부의 토핑콘크리트의 두께와 와이어메쉬의 배근유무이며, 총 8개의 슬래브 간 접합부 실험체 중 4개의 면내전단실험과 4개의 면외방향 전단실험을 수행하였다. 실험의 결과는 균열하중, 파괴하중, 파괴양상, 강성 및 연성도의 측면에서 분석하였으며, 실험결과를 설계하중과 비교 검토함으로써 최적의 디테일을 개발할 수 있는 실험적 근거를 제공하도록 하였다. 실험결과, 슬래브 간 접합부에 무수축 모르타르를 타설한 경우에는 토핑두께 30mm의 보통 콘크리트를 사용한 것과 유사한 구조성능을 발현할 수 있는 것으로 평가되었으며, 와이어메쉬의 보강효과는 내력 및 강성보다는 연성의 증가에 크게 기여하는 것으로 나타났다. 또한, 토핑콘크리트의 두께에 따른 설계하중과의 비교를 통하여 적절한 디테일 설계를 할 수 있는 기초적 자료를 제공하였다.

풍하중 및 지진하중등 횡하중이 작용하는 무량판 슬래브는 전단파괴와 같은 취성파괴를 지연시키기 위해서 충분한 전단강도와 연성능력을 보유하여야 한다. 본 연구에서는 반복 횡하중을 받는 무량판 슬래브의 전단강도와 변형성능을 고찰하기 위하여, 무보강 및 전단 보강된 총 4개의 내부기둥-슬래브 접합부를 실험하였다. 실험결과, 전단보강 슬래브의 이방향 전단강도는 무보강 슬래브보다 최대 1.5배까지 증가시켜 적용하는 콘크리트구조설계기준(KCI)과 ACI 318-02 기준은 중력하중만이 작용하는 경우에는 적절하나 조합하중 특히 횡하중의 영향이 클 경우에는 매우 불안전측 이었다. 한편, 변형성능 측면에서 슬래브-기둥 접합부의 1.5% 횡변위 성능을 확보하기 위하여 이방향 전단강도에 대한 중력하중비를 40%이하로 제한한 ACI-ASCE 352 위원회의 권고는 안전측인 것으로 나타났다.

본 연구에서 내부 공간을 확장시키기 위한 평면확장형 공동주택 리모델링에 있어서 기존 슬래브와 신규 슬래브 접합부의 횡방향 하중 전달 성능을 평가하기 위한 실험을 수행하였다. 슬래브의 접합연결재로 후 매립 Dowel 철근을 사용하였다. 기존 슬래브는 철거 예정인 기존 아파트로부터 채취하였으며, 휨성능을 향상시키기 위하여 탄소판(CFRP)으로 보강하였다. 실험결과로부터 후 매립 Dowel 철근으로 접합된 접합부 실험체가 최종파괴 시까지 완전합성거동을 하는 것을 확인하였으며, 충분한 극한성능 및 사용성능을 확보하고 있음을 알 수 있었다.