In this study, we focus on the feasibility of structural topology optimization for a steel-timber composite beam design of optimally allocating glue-laminated timbers into a web with openings under the condition of given steel flanges. The motivation of this study is to topologically take maximal stiffness harmonizing both tension and compression performance of the steel-timber composite beam and become the eco-frandly timber design for buidling members. As a result of this study, the key web-openings allocation becomes triangle spaces, i.e., empty or no materials, of optimal topologies of both a pure timber plate and a steel flange-web timber plate without web-openings. Several applicable examples verify the effectiveness of topology optimization for steel-timber beams with web-openings.

In this study, an experimental study was carried out to evaluate the bond shear performance according to the shear connector between the glue-laminated timber and steel interface. Ten block shear specimens were fabricated according to the configuration of the adhesive surface of wood and steel. In addition, four test specimens were produced according to the main variable shape of the wood-concrete shear connector. As a result of the block shear test, the shear strength of the steel-wood adhesive is shown to have a shear performance greater than the wood-wood shear strength. As a result of the push-out test according to the shape of the shear connector, the shear strength increased linearly with the attachment area. The complete composite behavior between the glued-laminated timber and the steel can be secured.

The high-temperature properties of mild steels were studied by comparing the test results of Kwon and the yield strength, tangent modulus predicted by the design provisions of ASCE and Eurocode(EC3). The column strengths for steel members at high temperatures were determined by the elastic and inelastic buckling strengths according to elevated temperatures. The material properties at high temperatures should be used in the strength evaluations of high temperature members. The buckling strengths obtained from the AISC, EC3 and approximate formula proposed by Takagi et al. were compared with ones calculated by the material nonlinear analysis using the EC3 material model. The newly simplified formulas for yield stress, tangent modulus, proportional limit and buckling strength which were proposed through a comparative study of the material properties and buckling strengths. The buckling strengths of proposed formulas were approximately equivalent to ones obtained from the formulas of Takagi et al. within 4% . They were corresponded to the lower bound values among the buckling strengths calculated by the design formulas and inelastic buckling analysis.

본 논문에서는 범용 유한요소프로그램 ANSYS와 ABAQUS를 이용하여 냉간성형강으로 조립한 조립기둥의 전체좌굴과 뒤틀림좌굴에 대한 비선형해석을 위한 모델링 기법을 소개한다. 냉간성형강의 경우 두께가 얇아서 국부좌굴 등 비선형거동을 보이기 때문에 좌굴에 대한 해석에 매우 섬세한 모델링이 필요하다. ANSYS의 내연적정적모델링에 의한 해석은 좌굴 극한점 부근에서 수렴의 문제를 발생하였지만, ABAQUS의 외연적동적모델링의 경우에는 좌굴 및 좌굴이후의 부재 거동에 대해서 안정적인 결과를 제공하였다. 또한 수치해석 결과는 좌굴실험을 통해 얻어진 축내력에 비해 높은 내력을 보여주고 있다. 이는 실험과정에서 발생하는 편심에 의한 영향으로서 수치해석에 의한 좌굴내력에 적정한 보정치의 적용이 필요하며 본논문에서는 기존 실험데이터와의 비교를 통해 0.88의 값을 제시한다.

The Adhesion method is general to reinforce steel structures using FRP(Fiber reinforced Plastic) material. Until recently in many studies, the adhesion method is being utilized. Most of the problem of this method have been eliminated. The bond performance is not enough due to the delaminate of epoxy between FRP and steel. In order to improve the problem, a bolt tighting, FRP sheet wrapping is to evaluation the degree of bond performance improvement in study.

IAI의 IFC를 기반으로 강 교량을 구성하는 부재의 상세 설계 정보를 표현하기 위한 방안을 제시하였다. 이를 위해 먼저 강교 부재 상세 설계와 관련한 설계기준, 구조계산서, 상세설계도면을 분석하여 실무에서 다루어지는 설계 데이터 항목과 이들의 표현방식을 분류하였다. 설계 항목을 기존 IFC 모델로 표현 가능한 것, 추가 모델이 필요한 것으로 나누었고, 보강재, 격벽, 현장 연결부, 그리고 전단연결재를 보다 체계적으로 표현하기 위한 속성 및 위상관계를 정립하였다. 마지막으로 본 연구를 통해 제시된 데이터모델을 기반으로 설계 정보 입력을 위한 프로그램을 구현하였다. 테스트용 교량에 적용하여 물리적 STEP 파일 생성함으로써 제시한 데이터 모델의 논리성을 확인하였다.

본 수치해석의 목적은 앵글 강부재의 극저사이클 파괴실험으로부터 얻어진 거동의 재현 빛 특히， 부재중에 서 가장 심한 웅력을 받는 부분에 대한 국소 웅력-변형률의 이력과 누적상황을 추적하는 것이다. 이를위해， 범용 구조해석 프로그램인 MSC/NASTRAN을 이용하여， 재료 및 기하학적 비선형을 고려한 대변형 3 차원 유한요소해석을 행하였다. 해석은 2 단계 즉， 해석 I 파 n 로 나누어 실시하였으며， 본 해석의 첸반적인 가동 은 실험결과와 매우 잘 일치하였다.

The durability of the steel structure can be affected by atmospheric corrosion environments as temperature, humidity, airborne salt etc.. However, atmospheric corrosion environments can be locally changed depending on structural condition and shape. To estimate the local atmospheric corrosion environments depending on structural member exposed to the marine environment, corrosion level of structural member in steel bridge was examined from exposure tests.

A steel tubular member has been generally used for the offshore structure. Its stucutral performance can be decreased due to corrosion damage under severe corrosion environment In this study, to examine the compression performance of steel tubular member depending on corrosion thickness, damaged ratio, FE analyses were conducted and compared.

In this study, It was purpose to provide preliminary data for extension of the applicability of deep corrugated steel plate composite members by steel grade and shear reinforcement method. From the result of flexural test on deep corrugated plates composite members using GR40 and SS590, positive moment capacity was increased about 28% by SS590 steel. But to change steel grade was proved to have insignificant effects for increasement of negative moment capacity. In the moment test result of same overlapping length, Increasement rate of positive and negative moment capacity was not significantly improved by increasing the number of bolt. It was estimated to be due to the characteristics of bolt connection such as distance between centers of bolts, edge distance of bolt. In the test result on the spacing of shear reinforcement, positive moment capacity was increased and deformation of negative moment was reduced as the distance decrease. In the test result on the shape of shear reinforcement, positive and negative moment resistance was increased about 2% ~ 7% by U shaped shear reinforcement. In conclusion It was estimated that moment capacity of deep corrugated steel plate composite members are depend on steel grade of deep corrugated steel plate, spacing of shear reinforcement and reinforcing bar.

This paper is to evaluate the flexural characteristics of 180MPa Ultra High Performance Concrete and reinforcing steel. In this study, the bending test is performed to evaluate the flexural characteristics considering lap-splice length. The stability of the lap-splice length proposed the structural design codes are evaluated on load-displacement. The results confirmed that the ductility has increased when the lap-splice has increased.

Recently, demand for construction aggregates is increasing due to the growth of construction site scale. As natural aggregate sources are becoming depleted due to high demand in construction field, the utilization of recycled aggregate (RA) as coarse aggregate in concrete is becoming more important. In this study, the authors analyze the mechanical properties of normal- and high-strength concrete beams using RA and investigate the usefulness of the minimum steal ratio for RA reinforced concrete beams. The experimental results show that application of the minimum steel ratio to RA reinforced concrete beams is possible.

The high-strength concrete slab confined by steel members, the possibility of thermal crack due to heat of hydration is high. These thermal cracks, it reduces the serviceability, safety and service life valuation of the structure, it is necessary to review.

Fatigue crack can be a controlling factor in the life of some welding components, such as vertical and horizontal stiffener. In this study, FE analysis was carried out to examine the three-dimensional fatigue crack penetration of gusset welded joint using the finite element analysis program FEMAP and FRANC3D. Three-dimensional fatigue crack penetration analysis result was compared with two dimensional fatigue crack penetration analysis result. From the FE analysis results, stress intensity factor(SIF) and crack propagation cycles were evaluated.

This paper presents a structural analysis method for moment-rotation capacity evaluation of press-braked steel girders and its application. The material-properties may be affected significantly due to the press-braking manufacture. Since strain-hardening induced by press-braking generally reduces the moment-rotation capacity, such the effects have to be thoroughly reviewed. The effects of the cold-working on the material properties, geometric imperfections and residual stresses were properly included into the analytical modeling. A series of nonlinear analyses were conducted for the Z-section girder models with the SM490 steel plates of 24mm thickness by using the Newton-Raphson method and the modified Riks method provided by the ABAQUS.

Steel Box-Truss Hybrid bridge consisted with steel box type in positive moment that is allowed to resist with low depth and truss type in negative moment not only has restriction of delivery but has to use high depth is new type bridge. In this study, structural analysis of Steel Box-Truss hybrid curved bridge with various curvature is performed and compared with member force and displacement of Steel Box-Truss Hybrid straight bridge. Also the applicable limited curvature of Steel Box-Truss Bridge form is proposed.

강재의 품질향상으로 강교에 있어서 재료자체의 파괴보다는 반복하중에 의한 피로균열 문제가 더욱 중요한 요소가 되었다. 재료의 항복으로 인한 교량의 붕괴 등의 사례는 거의 보고되고 있지 않지만 용접부에 발생하는 피로균열에 대한 사례는 매우 많이 보고되고 있다. 종리브와 횡리브, 데크 플레이트로 구성된 직교이방성 강바닥판의 피로응력은 강바닥판을 구성하는 요소들의 구성 형태 및 물성과 밀접한 관련이 있다. 본 논문에서는 Pelikan-Esslinger method와 signed Von-Mises 등가응력 개념을 활용하여 직교이방성 강바닥판의 피로응력을 산정하는 방법을 제시하고, 직교이방성 강바닥판 구성요소들의 구성형태와 물성을 변화시켜 피로응력에 미치는 영향을 분석하였다. 직교이방성 강바닥판의 피로응력과 구성요소의 상관관계 경향을 분석함으로써 설계 및 유지보수 시에 더 효율적인 대안을 찾는데 도움이 될 수 있을 것이다.