• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.325-326
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• 2012

Because steel frame has own characteristics as easy to work and structural safety, it is being increased application by the trend of construction industry has been more higher and larger in today. However, steel frame works have potential problem, so fundamental solution is needed for preventing serious accidents. Recently, self-supported steel joint for enhancing safety is developed in Korea, but this system has some limitations as convenience of work, retainment of consistent productivity. For complementing this limitations, we developed the new system named Automated wire control machine. This study is performed productivity of steel frame work by new system. The basis data for analysing productivity is collected from field test.

• 토지주택연구
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• 제7권4호
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• pp.271-279
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• 2016

Recently developed trenchless construction methods ensure stability for the ground settlement by inserting steel pipes along the underpass section and integrating steel pipes before ground excavation to form pipe-roof. This study is to confirm the reinforcing effect of pipe-roof by measuring lateral earth pressure acting on the underpass constructed by the STS (Steel Tube Slab) construction method. For this purpose, lateral earth pressure was measured at the left and right side of the pipe-roof after installing earth pressure cells. As a result, lateral earth pressure was measured with considerable reduction because the integrated pipe-roof shared surcharge. Therefore, economic design for the underpass could be expected by sharing design load by pipe-roof. In addition, construction cost was analyzed according to the design-load sharing ratio by pipe-roof. As pipe-roof shares design load by 40%, the total construction cost can decrease by almost 10% in the case of four-lane underpass.

• 한국건설관리학회논문집
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• 제24권4호
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• pp.25-34
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• 2023

본 연구의 목적은 플랜트 건설에서 현장시공과 모듈시공에 대한 공사비를 산정하여 비교하는 것으로 공사비를 산정하는 대상을 Pipe Rack으로 한정하였다. 이에, 현장시공으로 준공된 국내 석유화학플랜트 건설사업 1곳을 사례로 선정한 후 비용자료를 조사하여 도출된 결과는 다음과 같다. Pipe Rack의 현장시공에 대한 직접공사비는 560억원으로 Steel Structure 251억원, Piping 308억원이며, 모듈시공에 대한 직접공사비는 607억원으로 Steel Structure 238억원, Piping 297억원으로 산정되었다. 또한, 현장시공과 모듈시공의 증감률을 비교해 보면, 재료비 1.9%, 경비 192.1% 증액되었으나, 노무비는 -9.1% 감액되어, 전체 직접공사비는 8.4%(47억원)가 증액되었다. 그리고 공사원가는 현장시공이 761억원, 모듈시공은 810억원으로 모듈시공이 6.4%(49억원) 증액되는 것으로 나타났다. 이와 같은 결과는 Pipe Rack을 모듈로 시공하는 경우 공사비가 증감되는 현황을 확인하기 위한 참고자료로 활용이 용이한 반면에, 모듈시공에 따른 간접적인 효과(노무인력 감소, 안전사고 발생 감소, 공사기간 단축 등)에 대한 연구가 필요하다.

• 국제초고층학회논문집
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• 제11권3호
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• pp.189-196
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• 2022

The practical difficulties of construction will impose many restrictions on the structural design, and the construction method can also provide unexpected ideas for solving design problems. Through the discussion of three issues closely related to construction in the structural design of Wuhan Center, this paper illustrates the importance of in-depth consideration of the construction situations in the structural design stage. The topics of "Connection between Embedded Steel Plates in Steel Plate Composite Shear Wall" and "Connection Joint between Outrigger Truss and Core Wall" are about how to facilitate on-site construction by simplifying and optimizing detail design. The topic of "Adjusting Internal Force Distribution by Optimizing Construction Sequence" is about how to make the construction process a tool for structural design.

• 한국건축시공학회지
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• 제9권2호
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• pp.31-38
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• 2009

In today's construction industry, buildings have been more complicated and higher, the demands of steel works have been increasingly concerned, which makes the schedule planning and management more significant. However, in actual construction sites, management is more based on a manager's construction experience than productivity data accumulated in previous projects. Moreover, most of the existing studies also featured a theoretical approach rather than an analysis of data straightforwardly collected in sites. In this study, a steel-erection site was visited to collect productivity data. The study found that there were significant disparities between aboveground work productivity and underground work; one tower crane operated work and two tower crane operated; and work productivity conducted in clear weather condition, cloud and rainy. However, the productivities of 'first node on ground' and 'second node on ground' were estimated similar. The productivity data collected and factors affecting the productivity will help managers to plan and control their similar steel-erection works. This study will also be beneficial for those performing related studies.

• Steel and Composite Structures
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• 제12권3호
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• pp.261-273
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• 2012

This study proposes and examines a circular composite bridge pier for seismic resistance. The axial and flexural strengths of the proposed bridge pier are provided by the longitudinal reinforcing bars and the concrete, while the transverse reinforcements used in the conventional reinforced concrete pier are replaced by the steel tube. The shear strength of this composite pier relies on the steel tube and the concrete. This system is similar to the steel jacketing method which strengthens the existing reinforced concrete bridge piers. However, no transverse shear reinforcing bar is used in the proposed composite bridge pier. A series of experimental studies is conducted to investigate the seismic resistant characteristics of the proposed circular composite pier. The effects of the longitudinal reinforcing bars, the shear span-to-diameter ratio, and the thickness of the steel tube on the performance of strength, ductility, and energy dissipation of the proposed pier are discussed. The experimental results show that the strength of the proposed circular composite bridge pier can be predicted accurately by the similar method used in the reinforced concrete piers with minor modification. From these experimental studies, it is found that the proposed circular composite bridge pier not only simplifies the construction work greatly but also provides excellent ductility and energy dissipation capacity under seismic lateral force.

• 한국건축시공학회지
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• 제12권6호
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• pp.636-647
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• 2012

Construction projects have become so large, complicated and incredibly high-tech that process management is currently considered one of the most important issues. Unlike typical manufacturing industries, most major construction activities are performed in the open air and thus are exposed to various environmental factors. Many studies have been conducted with the goal of establishing efficient techniques and tools for overcoming these limitations. Productivity analysis and prediction, one of the related research subjects, must be considered when evaluating approaches to reducing construction duration and costs. The aim of this research is to present a quantified impact analysis of construction delay factors on construction productivity of a steel staircase system, which has been widely applied to high rise building construction. It is also expected to improve the process by managing the factors, ultimately achieving an improvement in construction productivity. To achieve the research objectives, this paper analyzed different delay factors affecting construction duration by means of multiple regression analysis focusing on steel staircase systems, which have critical effects on the preceding and subsequent processes in structure construction. Statistical analysis on the multiple linear regression model indicated that the environment, labor and material delay factors were statistically significant, with 0.293, 0.491, and 0.203 as the respective quantified impacts on productivity.

• Architectural research
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• 제15권3호
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• pp.167-174
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• 2013

Due to increasing competition of construction companies, it is required to optimize the management of construction projects and "lean" concepts are rapidly spreaded in construction industry. Steel work accounts for a large proportion in construction work, and a variety of attempts to efficiently perform steel work has currently made. And since rebar (Engineer-to-Order) can be engineered through design once order is placed, it gives the great impact on construction, thus, entire management is required. The purpose of this study is to present the method to increase the efficiency of field processing method of steel work in terms of lean construction. Once we examine process of steel work and identify the flow, we would like to analyze which processes should be improved through value analysis approach and present the improvement plans. Also, this study examines cases of field processing and factory processing, and it identifies the waste factors in the procurement process. Finally, this study would like to present the result of analysis from the perspectives of value. The rebar delivery process is divided into several steps and the duration of every step is surveyed. Using duration data, VAT (Value added time) can be calculated for analyzing the efficiency of the process.

• Steel and Composite Structures
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• 제20권5호
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• pp.999-1022
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• 2016

The use of Carbon Fiber Reinforced Polymer (CFRP) to strengthen steel structures has attracted the attention of researchers greatly. Previous studies demonstrated bonding of CFRP plates to the steel sections has been a successful method to increase the mechanical properties. However, the main limitation to popular use of steel/CFRP strengthening system is the concern on durability of bonding between steel and CFRP in various environmental conditions. The paper evaluates the performance of I-section steel beams strengthened with pultruded CFRP plate on the bottom flange after exposure to diverse conditions including natural tropical climate, wet/dry cycles, plain water, salt water and acidic solution. Four-point bending tests were performed at specific intervals and the mechanical properties were compared to the control beam. Besides, the ductility of the strengthened beams and distribution of shear stress in adhesive layer were investigated thoroughly. The study found the adhesive layer was the critical part and the performance of the system related directly to its behavior. The highest strength degradation was observed for the beams immersed in salt water around 18% after 8 months exposure. Besides, the ductility of all strengthened beams increased after exposure. A theoretical procedure was employed to model the degradation of epoxy adhesive.

• Steel and Composite Structures
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• 제32권4호
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• pp.521-536
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• 2019

The mechanical response of concrete-filled steel tubular (CFST) columns subjected to pure compression or uniaxial bending was studied in depth over the last decades. However, the available research results on CFST columns under biaxial bending are still scarce and the lack of experimental tests for this loading situation is evident. At the same time, the design provisions in Eurocode 4 Part 1.1 for verifying the stability of CFST columns under biaxial bending make use of a simplistic interaction curve, which needs to be revised. This paper presents the outcome of a numerical investigation on slender CFST columns subjected to biaxial bending. Eccentricities differing in minor and major axis, as well as varying end moment ratios are considered in the numerical model. A parametric study is conducted for assessing the current design guidelines of EN1994-1-1. Different aspect ratios, member slenderness, reinforcement ratios and load eccentricities are studied, covering both constant and variable bending moment distribution. The numerical results are subsequently compared to the design provisions of EN1994-1- 1, showing that the current interaction equation results overly conservative. An alternative interaction equation is developed by the authors, leading to a more accurate yet conservative proposal.