• KCI Concrete Journal
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• 제14권2호
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• pp.61-68
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• 2002

An experimental investigation on the flexural fatigue behavior of a RC bridge slab retrofitted with Carbon Fiber Sheet (CFS) is presented. The test slab was almost identical to the slab of a highway viaduct in terms of the amount of reinforcement, quality of concrete and thickness of the slab, which was 18cm. Repeated load corresponding to 3.0, 4.5 or 6.0 times of the design load was applied to the test slab. Normal type and high-elastic modulus type of CFS were used for strengthening. The test slabs were loaded in dry or wet condition. Two different types of an-choring system were adapted. Some of the test slabs were damaged by the repeated load and retrofitted by CFS, then loaded again to see the improvement of the fatigue life. Infrared Thermography was also performed to investigate the debonding condition of CFS. From the test results, Carbon Fiber Sheet can be applied to the RC bridge slabs as a feasible retrofitting material.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 추계학술대회 논문집
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• pp.455-462
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• 1999

Tn this paper. a numerical method for the system analysis of the slab track is presented. In the model rail is considered to have a distributed mass and to be supported by sleepers discretely on slab. The slab supported by discrete slab pads- isolators Put on floor is modelled by finite beam elements The system analysis for the same type floating slab laid in Puchon station is carried out using the developed program. Then the numerical results are compared with system requirements for slab track.

• 한국건축시공학회지
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• 제13권6호
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• pp.513-521
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• 2013

This study aimed to examine whether heat curing methods of concrete subjected to $-10^{\circ}C$ could be effective by varying the combination of heating cable and surface heat insulations. Three different concrete specimens incorporating 30% fly ash with 50% W/B were fabricated to simulate wall, column and slab members with dimensions of $1600{\times}800{\times}200$ mm for slab, $800{\times}600{\times}200$ mm for wall and $800{\times}800{\times}800$ mm for column. For heat curing combinations, Type-1 specimens applied PE film for slab, plywood for wall and column curing. Type-2 specimens applied double layer bubble sheet (2LB) and heating coil for slab, and 50 mm styrofoam for wall and column curing. Type-3 specimen applied 2LB for slab, electrical heating mat for wall and column inside heating enclosure. The test results revealed that the temperature of Type 1 specimen dropped below $0^{\circ}C$ beginning at 48 hours after placement due to its poor heat insulating capability. Type 2 and 3 specimens maintained a temperature of around $5{\sim}10^{\circ}C$ after placement due to favorable heat insulating and thermal resistance.

• 대한토목학회논문집
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• 제12권3호
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• pp.17-24
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• 1992

철근(鐵筋)콘크리트 슬래브교(橋) 설계시(設計時) 교각(橋脚)을 T형 및 ${\Pi}$형식으로 취하는 것보다 기둥만으로 슬래브를 직접 지지(支持)하도록 함으로써 유효공간(有效空間) 확보 뿐만 아니라 슬래브 자체(自體)의 내하력(耐荷力)을 이용함으로써 구조적(構造的)인 효율측면(效率側面)에도 유리하다. 그러나 기둥으로 지지된 슬래브교의 설계를 위한 휨모멘트계산은 아직 체계화(體系化)되어 있지 않은 상태이다. 중간지지점(中間支持點)의 종방향(縱方向) 최대휨모멘트를 유효폭개념(有效幅槪念)을 적용하여 가상지간(假像支間)을 이용한 단순보해석으로 간단히 구할 수 있는 방법(方法)에 대하여 연구하고 유효폭을 수식화(數式化)하였다. 주요변수(主要變數)는 지간(支間), 교폭(橋幅), 슬래브 두께 및 기둥단면(斷面)으로 하고 유한요소법(有限要素法)을 이용하여 단면력(斷面力)의 변화를 조사하였다.

• 소성∙가공
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• 제20권2호
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• pp.132-139
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• 2011

Three dimensional simulations were performed for the deformation of a slab in a roller hearth type slab reheating furnace. The main objective of this study was to examine the deformation pattern of the slab due to the shadow effect, i.e., the temperature difference between the upper and lower slab surfaces, in particular, the variations of displacement and effective stress in the vertical direction. A commercially available FE code, ANSYS Workbench $12.1^{TM}$, was used in a fully coupled thermo-elasticity analysis. Several cases with different slab surface temperatures were selected for the simulations. For the sake of simplicity, the temperature environment inside the furnace was assumed to be homogeneous for the upper and lower faces of the slab. Two cases of with different slab width were selected as model geometry. The deformation patterns were computed and explained in terms of periodicity and symmetry. The results indicated that the shadow effect leads to a significant displacement in the vertical direction and, thereby, is one of the main reasons for the separation of the slab and its supports. These simulations also predicted that the deformation is more severe along the transverse direction than along the longitudinal direction.

• Structural Engineering and Mechanics
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• 제81권6호
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• pp.737-750
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• 2022

Timber-Concrete Composite construction system consists of combining timber beam or deck and concrete with different connectors. Different fastener types are used in Timber-Concrete Composite systems. In this paper, the effects of two types of fasteners on structural behavior are compared. First, the notches were opened on timber beam, and combined with reinforced concrete slab by fasteners. This system is called as Notched Connection System. Then, timber beam and reinforced concrete slab were combined by new type designed fasteners in another model. This system is called as Notched-Slab Approach. Two laboratory models were constructed and bending tests were performed to examine the fasteners' effectiveness. Bending test results have shown that heavy damage to concrete slab occurs in Notched Connection System applications and the system becomes unusable. However, in Notched-Slab Approach applications, the damage concentrated on the fastener in the metal notch created in the slab, and no damage occurred in the concrete slab. In addition, non-destructive experimental measurements were conducted to determine the dynamic characteristics. To validate the experimental results, initial finite element models of both systems were constituted in ANSYS software using orthotropic material properties, and numerical dynamic characteristics were calculated. Finite element models of Timber-Concrete Composite systems are updated to minimize the differences by manual model updating procedure using some uncertain parameters such as material properties and boundary conditions.

• 한국농공학회논문집
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• 제59권1호
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• pp.97-107
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• 2017

In this study, the validity and applicability of the multipurpose fishway which has been constructed for the upstream migration of fish at Chuksan river in Uljin is assessed and analyzed by a commercial software. The upper slab types of fishway in this investigation are reinforced concrete slab (S1 type) and reinforced concrete slab with steel plate (S2 type). The three different sizes of subway passage ($0.8m{\times}0.1m$, $0.8m{\times}0.2m$, $0.8 m{\times}0.3m$) and velocities (0.6 m/s, 1.2 m/s, 1.8 m/s) of Chuksan fishway was investigated and compared for the Chuksan in government design code. The analysis showed that the maximum stress and bending moment of S1 type decreased 1~21 % and 12~27 % compared to the Chuksan in government design code, respectively. Also, the maximum stress of and bending moment of S2 type decreased 11~32 % and 27~39 %. From the numerical analysis, it was found that the S2 type was greatly effective and the subway passage size of $0.8m{\times}0.2m$ was most safe. This result can be utilized to be the basic data for design of the Multipurpose fishway.

• 화약ㆍ발파
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• 제27권2호
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• pp.19-25
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• 2009

벽식구조 아파트에 대한 재개발의 수요가 증가함에 따라 RC구조 아파트와는 다른 새로운 해체기술이 요구되고 있다. 본 연구에서는 벽식구조 아파트의 발파해체를 위한 기초적인 자료를 제공하기 위해 실시설계 도면을 토대로 벽식구조 아파트를 주동 형태 및 규모에 따라 분류하고, 아파트의 높이(H), 폭(B), 길이(L)의 발파 패턴 요소를 이용하여 벽식구조 아파트의 발파해체에 적합한 발파해체공법을 분석하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.597-602
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• 2007

It is proposed to analyze the vibration of slab with MTMD and vibration-induced noise. Substructure synthesis is introduced to develope the interaction between the slab and MTMD which are defined in different space and acoustic power is obtained from the velocity field of slab. Numerical analysis is performed to show that the vibration and noise of slab can be reduced by MTMD. A living room of wall type apartment including the wall and MTMD is modeled and analyzed by FEM program Numerical analysis shows that the vibration and noise control effect is different depending on the location and mass ratio of MTMD. Futhermore, noise is more effectively reduced when the vibration of higher modes of slab are reduced rather than lower modes.

• 한국지열·수열에너지학회논문집
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• 제13권4호
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• pp.1-7
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• 2017

The energy slab is a ground coupled heat exchanger equipped in building slab structures, which represents a layout similar to the horizontal ground heat exchanger (GHEX). The energy slab is installed as one component of the floor slab layers in order to utilize the underground structure as a hybrid energy structure. However, as the energy slab is horizontally arranged, its thermal performance is inevitably less than the conventional vertical GHEXs. Therefore, stainless steel (STS) pipes are alternatively considered as a heat exchanger instead of high density polyethylene (HDPE) pipes in order to enhance thermal performance of GHEXs. Moreover, not only a floor slab but also a wall slab can be utilized as a heat-exchangeable energy slab in order to maximize the use of underground space effectively. In this paper, four field-scale energy slabs were constructed in a test bed, which consist of the STS and HDPE pipe, and a series of thermal response tests (TRTs) was conducted to evaluate relative heat exchange efficiency per unit pipe length according to the pipe material and the configuration of energy slabs. The energy slab equipped with the STS pipe shows higher thermal performance than the energy slab with the HDPE pipe. In addition, thermal performance of the wall-type energy slab is almost equivalent to the floor-type energy slab.