Recently, the floor construction method of buildings is rapidly being replaced by the steel deck construction method of factory products from the past cast-in-place formwork method in order to shorten construction period, reduce labor costs, and improve constructability. In this study, the bending capacity of a newly developed lattice integrated rib-type deck plate that is economical and constructible was evaluated through a simple beam test. As a result of the experiment, the lattice integrated rib-type deck installed by adding rib to the existing flat deck had excellent initial rigidity and maximum load-bearing ability, confirming the feasibility of practical use. In addition, the test specimen in which the tensile rebar is not integrated with the lattice and deck has very low initial stiffness, which is insufficient to support the load at the construction stage, and new details need to be developed to overcome this.

본 연구는 교정공무원의 지각된 통제감과 직무소진 관계에서 고통감내력과 정서조 절곤란의 순차 이중매개효과를 검증하는 데 그 목적이 있다. 이를 위해 수도권(서울, 경기)에 소재한 3개 교정기관과 충청권, 경상권에 소재한 2개 교정기관에 근무하는 만 21세에서 만 59세 미만의 교정공무원 223명(남:189명, 여:34명)을 대상으로 온라 인 자기 보고식 설문조사를 실시하여 지각된 통제감, 직무소진, 고통감내력, 정서조절 곤란을 측정하고 순차이중매개효과에 대한 검증을 실시하였다. 연구 결과 첫째, 지각 된 통제감과 고통감내력 간의 관계 및 정서조절곤란과 직무소진 간 관계에서 유의한 정적 상관이 나타났다. 아울러, 고통감내력과 정서조절곤란 간의 관계에서는 유의한 부적 상관이 나타났다. 둘째, 지각된 통제감이 고통감내력과 정서조절곤란을 순차적으 로 경유하여 직무소진에 미치는 매개 효과가 유의한 것으로 나타났다. 이 연구는 지각 된 통제감이 직무소진의 감소로 이어지는 과정에서 고통감내력과 정서조절곤란을 순 차적으로 경유할 가능성을 시사한다. 이러한 결과는 지각된 통제감을 가진 내담자가 직무소진을 호소할 때 고통감내력과 정서조절곤란에 대한 개입의 필요성을 제시한다.

A bending experiment was conducted to verify the structural performance of the U-flange truss hybrid bean using rebars or steel pipes to reinforce the upper compression zone. As a result of evaluating the bending strength of the truss hybrid beam according to the Structural Design Standard (KDS 14 2020: 2022) by introducing the lattice member as a tensile resistance element, the following conclusions were obtained. Considering the lattice element as a tensile resistance element, the nominal bending strength was increased by 38.57 to 47.90 kN.m. As a result of reviewing the experiment as to whether the flexural member has proper ductility, it was found that it is desirable to place appropriate rebars, steel quality plans, and lateral restraints on the upper and lower parts of the hybrid beam to have sufficient ductility ratio.

A typical low and medium-sized neighborhood living facility in reinforced concrete building secures a high floor and pursues an efficient module plan(long span). Accordingly, research on the development of new hybrid beams that can innovatively reduce labor costs such as on-site installation and assembly while securing strength and rigidity is ongoing. In order to verify the structural performance of the U-flanged truss composite beam with newly developed shape, Experiments with various variables are required. Based on the results, this study is to evaluate the strength of U-flanged truss hybrid beam through the flexural strength of the Korea Design Code and experimental values. It was evaluated that nominal flexural strength was 110% to 135% higher than the experimental value.

최근 건축물의 보수보강 및 리모델링시 구조부재를 부착시키거나 고정하는데 있어서 시공의 유연성 및 용이성으로 후설치 부착식 케미컬앵커의 사용이 증가하고 있는 실정이다. 그동안 후설치 익스팬션앵커에 대한 내력평가는 지난 10년간 실 험을 통한 연구가 지속되어 설계기준식 제정등 어느정도 정립단계에 있으나, 부착식 케미컬앵커에 대한 해석 및 실험적 연구는 아직 미비한 실정으로, 현재 설계자와 시공자가 신뢰할 수 있는 명확한 설계기준이 없는 상태로서 외국의 설계기준에 의존하고 있는 실정이다. 따라서 본 연구에서는 부착식 캡슐형 및 주입형 케미컬앵커의 볼트직경, 매입깊이, 연단거리 그리고 앵커간격를 변수로 한 인발시험을 통하여 비균열 무근 콘크리트에 매입된 케미컬앵커의 인발내력에 미치는 제요소를 분석하고, 구조적 안 정성을 고려한 합리적인 부착식 케미컬앵커 설계를 위한 기초자료를 제공하는 것을 그 목적으로 한다.

This study aims to develop a form-finding algorithm for a single-layered pneumatic membrane. The initial shape of this pneumatic membrane, which is an air-supported type pneumatic membrane, is to find a state in which a given initial tension and internal pneumatic pressure are in equilibrium. The algorithm developed to satisfy these conditions is that a nonlinear optimization problem based on the force method considering the deformed shape is formulated, and, it’s able to find the shape by iteratively repeating the process of obtaining a solution of the governing equations. An computational technique based on the Gauss-Newton method was used as a method for obtaining solutions of nonlinear equations. In order to verify the validity of the proposed form-finding algorithm, a single-curvature pneumatic membrane example and a double-curvature air pneumatic membrane example were adopted, respectively. In the results of these examples, it was possible to well observe the step-by-step convergence process of the shape of the pneumatic membrane, and it was also possible to confirm the change in shape according to the air pressure. In addition, the calculation results of the shape and internal force after deformation due to initial tension, air pressure, and self-weight were obtained.

콘크리트가 충전된 강관 합성기둥은 화재 시 내부 콘크리트가 내력을 견딜 수 있어 높은 하중을 받는 건축물에 적용되고 있으나 높은 내화성능을 요구하는데 반해 이를 평가할 수 있는 방법은 제한되어 있다. 본 논문에서는 폭 700mm 이상인 무피복 대형합성기둥의 온도분포를 확인하기 위해서 수평가열로에서 3시간 내화실험을 수행하고 이후에 압축실험에 수행하여 잔존내력을 확인하였다. 실험 결과 3시간의 화재 노출 후에 폭 700mm 대형합성기둥은 57%의 잔존내력을 가지는 것으로 나타났으며, 재료의 화재 강도저감만을 고려한 잔존내력 예측은 내력을 낮게 평가하는 것으로 나타났다.

For the practical application of U-flanged Truss Hybrid beams, the flexural capacity of hybrid beams with end reinforcement details using vertical steel plates was verified. The bending test of U-flanged Truss Hybrid beams was performed using the same top chord under the compressive force, but with the thickness of the bottom plate and the amount of tensile reinforcement. The initial stiffness and maximum load of the specimen with tensile reinforcement have a higher value than that of the specimen without tension reinforcement, but the more tensile reinforcement, the greater the load decrease after the maximum load. In the case of the specimen with tensile reinforcement, because the test result value is 76% to 88% when compared with the flexural strength according to Korea Design Code, the safety of the U-flanged Truss Hybrid beam with the same details of the specimens can’t ensure. Therefore, the development of new details is required to ensure that the bottom steel plate and the tensile reinforcement can undergo sufficient tensile deformation.

The U-flanged truss hybrid beam is a new composite beam made by pouring concrete into the U-flanged truss beam. In this study, an experimental study was performed to verify the shear capacity of U-flanged truss hybrid beams with the newly developed end reinforcement details. For all specimens, the maximum shear strength was determined by shear failure of concrete in the loading point The detail reinforced with stirrups at the end zone can exhibit the greatest shear strength, but the method of reinforcing the end zone using vertical steel plates, which is a relatively easy method to manufacture, is considered to be the most effective detail in terms of shear strength and ductility. Also, in the case of U-flanged truss hybrid beams reinforced with vertical steel plates at the end zone, the shear strength can be evaluated on the safety side by using the Korea Design Standard formula.

Generally the non-bearing walls in apartment buildings in Korea are not considered as a lateral force resisting members for the design consideration. This engineering practice caused large crack damages and brittle fractures of the non-bearing walls when subjected to Pohang earthquakes in 2017 since those have not been designed for seismic loading. In this study, finite element analysis was conducted for slot type non-bearing wall connection system to reduce damages and concentrate damages to the designated damping device through separation from the structural wall members. Steel plate and dowel bar systems designed for the dissipation of seismic energies were modeled and analyzed to investigate the damage reductions. Finally, the test result and the analysis result were compared and verified.

U-flanged truss beam is composed of u-shaped upper steel flange, lower steel plate of 8mm or more thickness, and connecting lattice bars. Upper flange and lower plate are connected by the diagonal lattice bars welded on the upper and lower sides. In this study, the details of delayed buckling of lattice members were developed through reinforcement of the end section, in order to improve structural capacity of U-flanged Truss Steel Beam. To verify the effects of these details, the simple beam experiment was conducted. The maximum capacity of all the specimens were determined by the buckling of the lattice. The vertical reinforced details of the ends with steel plates, rather than the details reinforced with steel bars, are confirmed to be a valid method for enhancing the structural capacity of the U-flanged Truss beam. In addition, U-flanged Truss Steel Beam with reinforced endings with steel plates can exhibit sufficient capacity of the lattice buckling by the formulae according to Korean Building Code (KBC, 2016) and Eurocode 3.

This study introduces a newly developed PC non-bearing wall system to prevent the damage of RC wall-type apartments that have been heavily damaged by the 2017 Pohang Earthquake. In order to evaluate the performance of the developed PC non-bearing wall system, a static cyclic test is conducted. The prototype of test specimen is from the RC wall-type apartment which has been severely damaged by the 2017 Pohang Earthquake. The specimen with the conventional non-bearing wall system showed the similar damage of RC wall type apartment suffered from the Pohang Earthquake. In case of the specimen with the developed PC non-bearing wall system, cracks and damages were not transmitted between the walls due to the seismic slit and there were almost no cracks in the non-bearing walls. Therefore, the proposed non-bearing wall system, separated from the structural walls, could prevent spreading cracks to bearing walls and make it possible to effectively control damage due to earthquake loads.

To study the seismic resistance of the shear capacity of the RC beam-column joints of two-story and four-story RC buildings, sample buildings are designed with ordinary moment resisting frame. For the shear capacity of joints, the equations of FEMA 356 and NZ seismic assessment are selected and compared. For comparison, one group of buildings is designed only for gravity loads and the other group is designed for seismic and gravity loads. For 16 cases of the designed buildings, seismic performance point is evaluated through push-over analysis and the capacity of joint shear strength is checked. Not only for the gravity designed buildings but also for seismic designed buildings, the demand of joint shear is exceeding the capacity at exterior joints. However, for interior joint, the demand of joint shear exceeds the capacity only for one case. At exterior joints, the axial load stress ratio is lower than 0.21 for gravity designed buildings and 0.13 for seismic designed buildings.

This study was carried out to examine the effect of the presence of non-structural walls in apartment buildings subjected to an earthquake. It was believed that the presence of non-structural walls, which has not been considered in the structural design process, was usually built together with structural walls and this led to significant damages to the apartment buildings in Pohang earthquake, 2017. In this study, a 22-story apartment building was selected and modeled to simulate the seismic behavior due to earthquakes. The story drift, performance point, and compressive strain in the walls were the main parameters to evaluate the seismic performance with the presence of non-structural walls.

The push-out tests have been conducted on the specimens which consist of the steel beam with U-shape section and the continuous cap-type shear connector. Existing formulas for the elevation of shear connector capacity were investigated on the basis of test results. The shear capacities of continuous cap-type shear connectors distinctly declined as the diameters of side-hole in the shear connector increased. The rebars through side-hole for the transverse reinforcement improved the shear capacity of continuous cap-type connector by 20 to 30 percent. It was not feasible to obtain the appropriate capacity values of continuous cap-type shear connectors made of thin steel plate like those of in this study, using the existing formulas. The new formula for reflecting the shear strength of penetrative bars was proposed based on the shear equation of Eurocode 4. The slip capacities of continuous cap-type shear connectors were shown to exceed the limit value of 6mm for the sufficiently ductile behavior.

제한된 토지의 효율적 이용을 위하여 건물들이 점점 더 거대화, 초고층화 되어가고 있기 때문에, 대형합성기둥에 대한 수요가 증가하고 있는 추세이다. 선행 연구를 통하여 리브를 갖는 냉간성형강재를 사용하여 구조적으로 안정적이며 경제적 인 충전강관기둥(ACT Column Ⅰ)이 기존에 개발되었으나, ACT Column Ⅰ은 크기가 제한(618×618)되는 문제가 있기 때문에 새로운 폭 1m이상 고하중용 대형합성기둥의 개발이 필요하다. 본 연구에서는 폭이 커지고 접합부 형식이 단순해지는 대형합성기둥(ACT Column Ⅱ)를 제안하고, 바인딩프레임이 보강된 실험체를 중심압축가력하여 구조성능을 확인하였다. 콘크리트 충전 여부 및 바인딩프레임의 보강 폭과 면적을 변수로 한 바인딩프레임 보강 실험체를 중심압축가력 하여 실험체 최대내력 값과 KBC2016 합성구조 설계메뉴얼에 따른 설계내력을 비교한 결과 ACT Column Ⅱ이 대형합성기둥으로써 안정적으로 거동함을 확인하였다.

In 2017 Pohang Earthquake, a number of residential buildings with pilotis at their first level were severely damaged. In this study, the results of an analytical investigation on the seismic performance and structural damage of two bearing wall buildings with pilotis are presented. The vibration mode and lateral force-resisting mechanism of the buildings with vertical and plan irregularity were investigated through elastic analysis. Then, based on the investigations, methods of nonlinear modeling for walls and columns at the piloti level were proposed. By performing nonlinear static and dynamic analyses, structural damages of the walls and columns at the piloti level under 2017 Pohang Earthquake were predicted. The results show that the area and arrangement of walls in the piloti level significantly affected the seismic safety of the buildings. Initially, the lateral resistance of the piloti story was dominated mainly by the walls resisting in-plane shear. After shear cracking and yielding of the walls, the columns showing double-curvature flexural behavior contributed significantly to the residual strength and ductility.

U-flanged truss beam is composed of u-shaped upper steel flange, lower steel plate of 8mm or more thickness, and connecting lattice bars welded on the upper and lower sides. The hybrid beam with U-flanged steel truss is made in the construction site through pouring the concrete, and designated as U-flanged truss hybrid beam. In this study the structural experiments on the 4 hybrid beams with the proposed basic shapes were performed, and the flexural capacities from the tests were compared with those from the theoretical approach. The failure modes of each specimen were quite similar. The peak load was reached with the ductile behavior after yielding, and the failure occurred through the concrete crushing. The considerable increasement of deformation was observed up to the concrete crushing. The composite action of concrete and steel member was considered to be reliable from the behavior of specimens. The flexural strength of hybrid beam has been evaluated exactly using the calculation method applied in the boubly reinforced concrete beam. The placement of additional rebars in the bottom instead of upper side is proposed for the efficient design of U-flanged truss hybrid beam.