• Title/Summary/Keyword: Steel Structural Work

Search Result 338, Processing Time 0.026 seconds

Effect of mach peening treatment on fatigue crack growth retardation in structural steel alloy (마하피닝 처리에 의한 기계구조용 합금강의 피로균열전파 지연효과)

  • Kim, Min-Gun;Lim, Bok-Kyu;Park, Hong-Ki;Hwang, Jung-Gak
    • Journal of Industrial Technology
    • /
    • v.26 no.A
    • /
    • pp.69-73
    • /
    • 2006
  • Mach peening treatment is one of the various kinds of techniques to improve the fatigue properties. The mach peening process gives high-level work hardening and compressive residual stress near the surface layer, improving the fatigue strength. In addition, this treatment reduces slip bands that initiate the fatigue cracks near the surface. During impingement, a plastic indentation surrounded by a plastic zone is formed. Mach peening treatment characteristic is less energy consumption and is an environmental friendly processing methods that is not accompanied by pollution. It is machining process that can prevent fatigue fracture beforehand in structure using already as well as process of production. The test results showed that fatigue crack propagation delay appeared by drilling type 43%, mach peening type 110%.

  • PDF

An Analytical Study on the Bond-Properties of Axial Bars Embedded in Massive Concrete (매시브콘크리트에 배근된 주철근의 부착특성에 관한 해석적 연구)

  • 장일영;이호범;이승훈;변근주
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1992.04a
    • /
    • pp.143-147
    • /
    • 1992
  • Description of the behavior of the R.C structural members fixed on massive concrete is not normally generalization of recognized configuration for regular R.C. design guidanes. This can be due to the complexity of evaluation of internal resistancy and deflection changes of the members subjected to the various external forces. On the base of axially loaded member fixed on footing, however, the estimation of deflection changes due to flexural force shear force and rotational force is to be carried out in ways of specifying the bond characteristics of axial bars embedded in massive concrete. This work is to quantify adhesion of steel-concrete, initial concrete cracking stress near bar rib, maximum bond stress and residual stress in concrete respectively. In addition to quantification of them for particulate behavior, the suggestions of multi-linear bond stress-slip diagram made in carrying out finite element analyses for adhesion failure, examining concrete cracking status and reviewing existing experimental data lead to alternatively constructed relationship between bond stress and slip for a axial bars embedded massive concrete.

  • PDF

A Study on the Shape of Beam Attached CFT inner-side for Developing Column's Performance (콘크리트충전 강관기둥의 성능향상을 위한 내면부착 beam의 형상 연구)

  • Lee, Dong-Un;Yun, Hyug-Gee;Kim, Dea-Geon
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2015.05a
    • /
    • pp.21-22
    • /
    • 2015
  • The CFT(Concrete Filled Tube) system has been developed to behave well in a structural performance such as stiffness, stress, ductility, fire resistance that is derived from its mechanical advantages of composite structure. There were number of studies about unprotected CFT columns for improving their fire resistance through reinforcing bars or plates being placed inside the steel tube. It was also known that reinforcing plates of flat type need stiffeners in a certain distance to avoid their buckling failure so it cost as much as their using consequentially. This paper is planned to test the work of beam elements attached inner side of CFT depending on its shape. More discussions on beam's design could be followed after some fire tests accordingly conducted within this project.

  • PDF

Behaviour of lead-rubber bearings

  • Mori, Atsushi;Moss, P.J.;Carr, A.J.;Cooke, N.
    • Structural Engineering and Mechanics
    • /
    • v.6 no.1
    • /
    • pp.1-15
    • /
    • 1998
  • Experimental work undertaken to investigate the behaviour of lead-rubber bearings under compression and a combination of compression and shear or rotation has been reported on elsewhere. However, it is difficult to determine the state of stress within the bearings in terms of the applied forces and the interaction between the lead plug and the steel shims and elastomeric layers. In order to supply some of the missing information about the stress-strain state within the bearings, an analytical study using the finite element method was carried out. The available experimental results were used to validate the model and although agreement was not as good as expected (on account of difficulties in modelling the lead plug), the analyses did provide some information about the state of the stress within the bearing.

A Safety Evaluation on the Rubber Panel for Railway Crossing (철길건널목용 고무보판 안전성 평가)

  • 윤성철;정종덕
    • Journal of the Korean Society for Railway
    • /
    • v.5 no.2
    • /
    • pp.125-132
    • /
    • 2002
  • As the public use part of the railway and the road, the railway crossing is important to work properly by two transportation means. Also, It is important to provide the good face of friction on the railway crossing in aspect of protecting the railway crossing accident. Lately, the material of railway crossing panel is the wood, the asphalt, and the steel. As they have a various fault, it was studied to analyze the structural action of the new material, rubber panel. This paper analyzed eigenvalue, stress and displacement by truck passing weight, thermal stress and train moving weight, using the Finite Element Method model

Case Study : BIM for Planning, Simulating, and Implementing Complex Site Logistics

  • Kim, JongHoon;Cohen, Fernando Castillo
    • Journal of KIBIM
    • /
    • v.5 no.4
    • /
    • pp.47-52
    • /
    • 2015
  • This paper presents a case study using Building Information Modeling (BIM) for planning, simulating, and implementing complex site logistics in a headquarter office building construction project in Silver Spring, MD. As part of the project a prefabricated 92ft structural tube steel pedestrian connector bridge was installed between two adjacent buildings in the city of Silver Spring, MD. There were multiple significant challenges to deliver, offload, prepare, and install the connector bridge safely, on time, and with the minimum disturbances to the neighbors. BIM was of the foremost importance to visualize, simulate, analyze, improve, and communicate the site logistics plan from delivery to installation of the connector bridge. As a result of the effort, GC of the project was able to prepare a highly detailed plan, communicate it effectively to all stakeholders, and flawlessly execute the work as planned. This case study would provide a useful reference for contractors who are seeking a better planning method that enables generation of more accurate, implementable, optimized plans for complex site logistics.

Structural Performance Evaluation of Reinforced Concrete Beams with Externally Bonded FRP Sheets (RC 구조물에 적용된 부착식 휨보강공법의 보강성능 평가)

  • Hong, Geon-Ho;Shin, Yeong-Soo
    • Journal of the Korea Concrete Institute
    • /
    • v.15 no.1
    • /
    • pp.78-86
    • /
    • 2003
  • Reinforced concrete beams are often retrofitted with various FRP composite sheets. This paper is focused on the comparison of structural performance of various FRP sheets and proposal of the retrofitting design formula. Effects of the FRP kinds(AFRP, GFRP, CFRP) and the reinforcing steel ratio on behavior of the retrofitting beams are tested and analyzed with particular emphasis on the maximum load capacity, stiffness, and ductility. The experimental work included 4 point flexural testing of 3.2m span reinforced concrete beams with bonded external reinforcements. The results show that the difference of FRP kinds is not large and the flexural load capacity is mainly affected by stiffness of the retrofitting materials. This paper also proposes the design formula on the retrofitting reinforced concrete flexural members and checks with this experimantal work and previous research results.

A Convergence Study through Durability Analysis due to the Configuration of Automotive Lift (자동차 리프트 형상에 따른 내구성 해석을 통한 융합 연구)

  • Choi, Kye-Kwang;Cho, Jae-Ung
    • Journal of the Korea Convergence Society
    • /
    • v.10 no.12
    • /
    • pp.281-286
    • /
    • 2019
  • To repair the underside of the car, a repairman has to enter under the car body. But this work can make it difficult for him to fix it and the injuries can occur. To solve these difficult problems, the developed equipment is the automotive lift. In this study, three kinds of lift models 1, 2 and 3 were designed and the material properties of the structural steel were applied. As the same load were applied under the same conditions on all models, the structural analyses were conducted. Models 2 and 3 were shown to have the structural deformation less than model 1. Also, models 2 and 3 were shown to be more stable than model 1 structurally. By utilizing the design data on a convergence research through durability analysis according to the configuration of automotive lift obtained on the basis of this result, the esthetic feeling can be shown by being converged onto the automotive repair equipment parts at actual life.

Mobile Augmented Reality for Teaching Bar Placing (철근 배근 교육을 위한 증강현실 컨텐츠 개발)

  • Park, U-Yeol
    • Journal of the Korea Institute of Building Construction
    • /
    • v.18 no.5
    • /
    • pp.471-477
    • /
    • 2018
  • The purpose of this study is to develop an mobile augmented reality for students to learn bar placing work, which is increasingly utilized in the construction field. In order to improve the understanding of the structural drawing, a structural drawing is used as a marker image, and an augmented reality is realized by superimposing a virtual 3D bar placing model that is placed according to the structural drawing on the screen. In addition to the 3D modeling, the contents are developed so as to help students to learn the interpretation method of 2D drawings, the development and splices of reinforcing steel, bar fabricating practice according to KCI structural concrete design code, and the process of bar placing. The results show that the augmented reality is positively evaluated in terms of interface style, perceived usefulness, perceived ease of use, perceived enjoyment, attitude toward using, and intention to use. The augmented reality is worth to be introduced because it has advantages of visualization and interaction in terms of education.

Evaluation of Seismic Performances on Prestressed Composite Coupling Beams with Discontinuous Webs (불연속웨브가 도입된 프리스트레스트 합성연결보에 대한 내진성능 평가)

  • Oh, Jae Yuel;Lee, Deuck Hang;Choi, Seung Ho;Kim, Kang Su;Yi, Seong Tae
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.17 no.1
    • /
    • pp.133-142
    • /
    • 2013
  • The shear wall system with coupling beams has been known as an effective means for moderate and high rise buildings up to 40 stories, because this structural system can provide the enhanced lateral stiffness compared to individual shear walls. Typical reinforced concrete coupling beams have difficulties in construction due to complicated reinforcing work on site, and steel coupling beams also have disadvantages in economical point of view because of a large number of stiffeners required for its stability under lateral loading. To overcome these disadvantages in existing coupling beam systems, this study developed the prestressed composite coupling beam with discontinuous webs, which have improved constructability, economic feasibility, and reduced sectional size. The reversed cyclic loading test on two prestressed composite coupling beams with discontinuous webs having different shear reinforcement ratios have been conducted to investigate their structural performances, and test results showed that the proposed composite coupling beams had good seismic performances.