Earticle

본 연구에는 다 지지조건을 가지는 슬래브 구조물의 자유진동 문제에 대하여 SIMP방법에 의한 재료 위상 최적설계 MATLAB 프로그램을 개발하고 동적 위상 최적화의 수학적 모델링에 필요한 집중질량과 분포질량의 등가조합 질량행렬을 유도하였다. 또한 강성행렬과 질량행렬에 벌칙 인자가 도입된 관계식과 경사도 기반 최적화방법인 MMA 알고리즘, MATLAB 고유치해석(명령어 Eigs) 박스7)를 이 용하여, 여러 가지 예제를 해석함으로써 다음과 같은 결론을 얻을 수 있었다. (1) 본 연구에서 개발한 동적 위상 최적설계 MATLAB 프로그램은 기존의 정적 위상 최적설계 MATLAB 프로그램 알고리즘 안에 구조해석을 위한 고유치해석 Eigs 함수를 적용함으로써 간편하게 구현 가능하였다. (2) 보-기둥 시스템을 연결하는 슬래브 구조물은 자유진동 위상 최적설계 문제에 대하여 보강재로서 구현되는 최적위상이 지지조건에 민감함을 알 수 있다. (3) 위상 최적설계 문제에 대하여 부피 제약조건이 클수록 수렴하는 최대 고유진동수가 감소한다. (4) 위상 최적설계 문제에 대하여 지지조건이 많을수록, 즉, 켄틸레버형(1변지지), 2변지지, 4변지지 슬래브 일수록 보강재가 보유하는 최대 고유진동수가 점점 감소한다.

The goal of this study is to present conceptual information of optimal design of slab structures often used for main building frames by using topology optimization method. Topology optimization method is well-known as an optimal material distribution tool to extract both optimal shape and topology, i.e. connectivity of members deposited by a given material quantity, which has been mainly evaluated in engineering fields such as mechanics, electronics, ship, and aero industries. This study targets design of mega structures like as structures for civil or building industries, not above-mentioned vitalized engineering fields. Design results of this study may have a limit of only producing basic conceptual information for practical design due to inexact design conditions and a lot assumptions. Therefore note that there are many supplementary and insufficient components for practice in this study, which have to be improved in the future. Topology optimization problem presented in this study is to determine the layout of material of specified volume in a domain that maximizes the first natural Eigenfrequency for dynamic responses under a given set of boundary conditions. Numerical applications showing appropriate optimal shapes of slabs with varied supports verifies the present topology optimization method is practically an alternative to produce a conceptual information of material distribution for practical designs of building frames.

This study conducted an experiment to verify the flexural reinforcement effect based on the state of damage by reinforcing damaged reinforced concrete slabs with composite mortar, in order to ascertain the effect of reinforcement construction methods verified to improve the strength of the structure and noise between floors on actual buildings. The method of experiment was conducted based on the “2017 Safety Inspection and Precise Safety Diagnosis Guidelines” of the Korea Infrastructure Safety and Technology Corporation, and the damage on the actual specimen was determination based on the displacement value occurring on the specimen. The experiment of introducing damage was set to a scope that can be reinforced to a state before the reinforced bar yielded, and only the damage of composite mortar was induced to conduct the experiment. The method of damaging the composite mortar was examined by comparing the values of the concrete material experiment result and the values of the composite mortar induced by an existing equation. The principal variables of the bend experiment included the wire mesh diameter, use of POSS, and damage levels 1, 2 and 3, and a total of 10 specimens were produced.

This study proposes a construction method reinforcing with composite mortar using Ethylene-Vinyl Acetate Copolymer (EVA) used as an environmentally friendly noise reduction material in Korea and other countries, POSS nano complex (Polyhedral OligomericSilses-quioxaneS) and wire mesh. A total of 12 specimens were produced according to slab thickness, wire mesh diameter, and ratio of reinforcement material in order to evaluate the strength of the composite concrete slab specimen produced using the proposed construction method. The final form of destruction, performance against force, and strength and malleability were evaluated based on the flexural compression, and a calculation equation of the slab reinforced with wire mesh and composite mortar was analyzed by comparing the values of the experiment and the values of the calculation equation proposed by existing theses.

Recently, Effective Width Beam Method has widely been researched in analysis method of Flat-Plate Slab System which is by the action of lateral load. Effective Width Beam Method is also useful especially in a general-purpose program, so it is being used widely. Actually, Effective Width Beam Method is mainly focused on lateral displacement which can happen in a plane that has a same span when lateral load is given and column-slab connection unbalance Moment, but studies about a plane which is a irregular span has not been studied enough. So we found that in condition of Flat-Plate Slab system which has irregular span plane when lateral load is given, output of lateral displacement is not much related with span, but column-Slab connection unbalance moment is influenced much by span after comparing the output of Column-Slab Connection Unbalance Moment and lateral displacement which are applied to Effective Width Beam Method with the Finite Element Method which has the exact output in Flat-Plate Slab system.

Report on the propagation characteristics of terahertz (THz) dielectric slab waveguides affected by laterally misaligned coupling conditions. The TM₀ mode is effectively launched when THz waves are coupled near the lateral center of the waveguide, On the other hand, if the coupling position is shifted laterally, higher-order asymmetric modes such as TM₁ and TM₃ become dominant. The coupling of incident THz waves at the center results in leaky mode behavior for longer wavelengths, whereas shorter wavelengths remain guided. In contrast, off-center coupling induces leaky mode characteristics over nearly the entire spectral ranges. These differences are distinguishable in the time-domain signals measured by THz time-domain spectroscopy, thus allowing the implementation of a time-domain prism for spectroscopy. The systematic investigation of THz slab waveguides may contribute to the realization of multifunctional optical devices for Tz sensing, imaging, and high-speed wireless communications, as well as to the analysis of optical properties in THz measurement systems.

There are two distinct features in Korean apartments. The first is Ondol, a floor radiant panel heating system that consists of an array of heating coils buried into a hard mortar finish. This allows residents to stand on the hard floor without shoes on. Next is a structural system composed of load bearing walls and slabs instead of beams and columns. Bare feet on hard surfaces cause severe noise from their impact with the floor. Furthermore, the tight and wide bonding between the slabs and the load bearing walls effectively transmits noise to the rooms underneath. This type of impact source cannot be simulated by a standard tapping machine, and may not be efficiently protected by usual floating floors. Four standard floor structures were introduced in the building code established in 2005 and all have 210mm thick floor slabs,. However, there are over five-million apartment units built before 2005, most of them having 135mm slabs. This study deals with a systematic approach to improve the performance of insulation used to absorb impact noise for apartments having shallow 135mm slabs. The construction between floors is investigated, specifically the following four components and their roles: Suspended ceiling and plenum (slab and its stiffness), thickness of the slab, the floor floating system, and resilient panel (for Ondol) support system.

The purpose of this study is comparison and analysis between standard impact source and human impact source. also showing characteristic of general slab and hollow slab when each impact sources is applied in general slab and hollow slab and comparing and analysis of characteristic in slab. As a result, load of tapping machine was difference to load of human light-weight impact source. and bang machine had difference on load. so we think we need additional studies about standard heavy-weight impact source to supplement this difference. and we can have decreae load of running impact source if we will use hollow slab having hollow proportion under 40% in application of slab about running impact source.

고층건물의 건설이 증가함에 따라, 건축물의 자중을 저감하면서 층고를 절감하고 장스팬 구현, 공기 단축 등을 목적으로 기존의 바닥구조 시스템을 개선한 중공슬래브 시스템에 대한 관심이 고조되고 있다. 중공슬래브는 콘크리트 물량저감으로 장스팬을 구현할 수 있고 이산화탄소 배출량을 감소시켜 친환경적이라는 장점이 있다. 하 지만, 기존 중공재(스티로폼)를 적용한 중공 슬래브는 화재발생시 유독가스가 발생하며, 이에 대규모 인명피해가 발생할 가능성이 높다. 따라서, 본 연구에서 개발된 유독가스 유출방지 중공 PC 슬래브의 구조성능을 검토하기 위 하여 슬래브 형상, 철근배근을 실제 실험체와 동일하게 모델링하여 유한요소해석을 수행하였다. 공극의 개수를 변 수로하여 해석을 수행하였다. 통풍구의 개수에 따른 최대변위 및 최대하중, 균열폭, 응력 등 PC 슬래브의 휨성능 을 평가하였다.

As the construction of high-rise buildings increases, interest in the hollow slab system that improves the existing floor structure system for the purpose of reducing the height of the floor while reducing the self-weight of the building, realizing a long span, and shortening the construction period is increasing. However, the hollow slab applied with the existing hollow material (styrofoam) generates toxic gas in the event of a fire, which is likely to cause massive casualties. Therefore, in order to examine the structural performance of the hollow PC slab for preventing leakage of toxic gas developed in this study, a finite element analysis was performed by modeling the slab shape and reinforcement in the same way as the experiment. the bending performance of the PC slab was evaluated, such as the maximum displacement, maximum load, crack width, and stress according to the number of Ventilation.

When there is a composite effect by concrete slab, in positive bending moment, it moves to a concrete slab side compared with the case where a composite effect does not have a neutral axis position. Consequently, when there is a composite effect, in positive bending moment, there are elastic rigidity, a rise of strength, and a restraint of horizontal buckling and upper flange local buckling. On the other hand, as for the bottom flange of a steel frame, the big degree of stress compared with an upper flange. Furthermore, to the same growth ability steel material, it bends to the lower flange fracture of a composite girder, and growth ability becomes small compared with a pure steel frame beam.

This study performed structure analysis to check floor's Out-of-Plane Stiffness for improvement of structure's performance by the 3D finite element method. Analyzing the structure, the key Point is to numerically compare structure's displacement, story drift, natural period and base shear force considering whether floor's Out-of-Plane Stiffness or not. The used analysis model has 十typed shape plane having accessibility, visual and well-ventilation compared with general regular-plane. As a result of the analysis, the structure's stiffness on earthquake load is increased by considering floor's Out-of-Plane Stiffness. Therefore, the analysis considering floor's Out-of-Plane Stiffness has benefit of economical design and reducing the analysis error compared with the diaphragm action of slab as general analysis.

The object of this study is theoretically and experimentally investigated to flexural behaviors of form deckplate slabs using wire mesh. The wire mesh instead of deformed bars is used to improve convenience of construction. Simplifying the stage of processing and assembling reinforcing bars, the efficiency in reinforced concrete construction are increased. Total 12 specimens were tested with oil-jack system of 1,000kN capacity. Test variables are concrete slab height(150mm, 175mm), types of main bars(1-D6, 2-D6, 3-D6) in compression and tension regions, and width in bottom face of deckplate(600mm, 690mm). The vertical loading by monotonic is applied to investigate the yielding strength, maximum strength, initial stiffness and failure modes. Test results are as follows ; (1) The concrete slab using wire mesh has excellent constructionability because the interval of the wire mesh will be able to regulate freely with option. (2) Higher stiffness and strength was shown that more the wire mesh was, the thicker the slab was. (3) The maximum strength of slab using wire mesh instead of reinforced bars is 1.05 1.72 times than those of calculated results.

This study is to develop the prefabrication of slab reinforcing bar unified with spacer to deal with insufficiency of skilled hand and rise of labor costs, and to improve the quality of construction. Accordingly, examined the structural safety, the constructional efficiency and spot application of unified prefabrication which were determined through a test of spacer strength and prefabrication deflection, then obtained the following consequences from these research results. 1) As a result of the spacer strength test, more than two reinforcing bars were required to satisfy spacer strength. 2) The deflection of prefabrication measured by test with a width between spacers, a gap between top-bars and the diameter of top-bar as variables indicated that the behavior of the prefabrication maintained linear when the concentrated load remained below 3kN, and the results of the prefabrication test and the computer program interpretation were similar. 3) As a result of analyzing the construction cost per ton to apply the prefabrication to spot, the construction cost of prefabrication method was just 103.1% of that of the existing one. 4) The arrangement of bars turned out to be about 1.1% more economical than the cost of existing method, and the labor cost turned out to be four times higher than the existing method, nevertheless cost of spot prefabrication turned out to be 53.6% of man power more economical.

본 연구는 슬랩 할당자(slab allocator)를 이용한 개선된 메모리풀을 제안한다. 이 방법은 메모리풀의 메모리 블록 집합을 할당 상태에 따라 동적으로 재배열한다. 동적 재배열된 메모리 블록 집합은 단일 메모리 블록 집합의 단편화를 줄이고, 할당된 메모리 블록의 지역적인 특성을 유지해준다. 단일 메모리 블록 연결 구조의 메모리풀은 메모리 할당 및 반환 요청을 처리하기 위해 전체 메모리 블록 집합을 탐색해야 하지만, 동적 재배열된 메모리 블록 집합은 탐색 범위를 제한하여 메모리풀의 메모리 블록 할당 및 반환 성능을 향상시킨다. 이를 통해 얻은 성능 향상을 동적 메모리 할당처럼 다양한 크기의 메모리 블록을 할당할 수 있는 메모리풀을 구성하는데 사용할 수 있다.

In this paper, we propose an improved memory pool using slab allocator. Our method dynamically rearranges memory block sets of memory pool by their state of usage, so it decreases fragments of memory blocks and keeps a locality more than a linked list structure of a single memory set. A memory pool that has a single memory block set searches all memory blocks to satisfy requests, but dynamically rearranged and classified memory block sets reduce its search range, improve performance of a memory pool. The proposed memory pool can allocate memory blocks of a various size by this improvement.

specimens for RC and SC wall-slab joint was tested. To investigate the joint performance of the specimens, distribution of shear force and fixidity between wall and slab was surveyed by monotonic loading. We selected 3 types of transfer mechanism of shear force to the wall-slab joint ; 1. The shear force resister by the friction on the joint surface, 2. The shared shear force by the shear plate, 3. The shared shear force by studs on the joint surface. and evaluate the degree of contribution of each part in shear transfer. Especially, slippage of the top rebar was investigated to evaluate the fixidity of the wall-slab joint.

연구목적: 본 논문에서는 이와 같은 배경을 근거로 충격하중 재하시 신소재 섬유로 보강 한 콘크리트 슬래브 거동을 연구하는 것을 주 목적으로 알루미늄 섬유를 이용한 AFRP로 보강한 콘크리트 슬래브 중앙의 강재를 자유낙하 시켰을 때 충격실험을 검토하고자 한 다. 연구결과: 신소재를 콘크리트 부재의 보강재로 이용하는 연구는 정적 하중하에서 휨 및 전단에 관한 연구나 반복하중 하에서 피로하중에 관한 연구와 PC 보에서의 적용에 관한 연구 등이 많이 보고 되고 있다. 결론: 신소재를 콘크리트 부재의 보강근으로 이용하는 연구의 일환으로 본 논문에서는 알루미늄 섬유로 보강된 조립상 AFRP 로트를 이용한 콘크리트 슬래브를 설치하여 동적 거동에 대해서 실험을 실시하였다.

Purpose: In this paper, based on this background, the main purpose of studying the behavior of concrete slab reinforced with new material fiber in impact loading is investigated by AFRP using aluminum fiber. Results: Research on the use of new materials as reinforcing materials for concrete members has been carried out in many fields such as flexural and shear tests under static loading, fatigue loading under cyclic loading, and application to PC beams. However, And the issue of plate elements is still at a basic stage. Conclusion: In this paper, the dynamic behavior of reinforced concrete slabs is investigated by using AFRP rod reinforced with aluminum fiber.

지하주차장의 안정적인 결로저감을 위해서는 단열성능의 향상이 보다 효과적인 대안으로 검토될 수 있다. 구조체의 단열성능을 높여 지하주차장의 결로를 저감하는 방법인 단열배수판의 결로방지 성능에 대해서는 건설시장에서 실제 적용되고 있는 상황에 비해, 실측이나 해석을 통하여 검증되지 못한 부분이 많다. 본 연구에서는 해석적인 방법을 통해 단열배수판의 성능을 분석하고 효과적인 시공방법을 분석하고자 하였다. 분석대상은 지하구조체 중 사용자에게 가장 불편함을 유발할 수 있는 바닥구조체로 설정하였으며 여기에 단열배수판을 다양한 방법으로 적용하였을 때 슬래브표면온도 상승효과를 전열해석프로그램을 이용해 예측하였다.

The purpose of this study is to investigate the surface temperature increase of the slab in underground parking lot by the construction methods of drainage plate with insulating layer(hereafter DPIL). This investigation used the heat transfer simulation tool Heat 2 for the evaluation. The construction methods considering 4 factors such as plain concrete thickness, implementation area of DPIL, thickness of insulating layer of DPIL and implementation of external insulation with DPIL are used for the establishment of simulation cases. The results of evaluation indicate that plain concrete is not effective solution for the surface temperature increase of the floor surface temperature. On the other hand, the implementation of DPIL shows the significant increase of the surface temperature. Removing the thermal bridge with the implementation of DPIL at the wall as internal insulation or the implementation of external insulation with XPS are can be the effective solutions.

This research examines basic property of sub-slab concrete mixed with recycled coarse aggregate, according to different unit quantity, replacement ratio of fine and coarse aggregate, BFS, and FA; the purpose is to encourage use of recycled aggregate. In case of fresh concrete, the fluidity increased along with the replacement ratio for recycled coarse aggregate; the air volume became larger in mixed concrete than in plain as the replacement ratio for recycled coarse aggregate increased. Mass for unit volume declined with the increasing replacement ratio. As for hardened concrete, compressive and tensile strength of mixed concrete reached over 80% of plain concrete, up to the replacement ratio of 30%. For drying shrinkage, the change in length became greater for mixed concrete than for plain as the replacement ratio increased.