• 한국건축시공학회지
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• 제10권3호
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• pp.121-128
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• 2010

본 연구에서는 건설공사의 합리적인 공사비 산정을 위하여 기존 표준품셈의 문제점을 개선하고, 새로운 적산 모델을 도입한 작업조 기반 표준품셈을 제안하고자 한다. 그리고 공동주택 시멘트 액체방수 공사를 대상으로 건설공사의 적산기술과 시공능력을 향상할 수 있도록 작업조구성과 시공프로세스를 체계화하였다. 또한 공동주택에서 욕실부분 시멘트 액체방수 공사를 대상으로 전용면적 $84{\sim}85m^2$, 전용면적 $125{\sim}184m^2$의 노무량 및 생산성을 분석하고 현행 표준품셈과 작업조 기반 품셈의 특징을 비교 분석하였다. 본 연구를 통하여 공동주택 시멘트 액체방수 공사의 현행 표준품셈과 작업조 기반 품셈을 서로 비교하였을 때, 전용면적 $84{\sim}85m^2$에서는 방수공은 평균 1.91~2.13배, 보통인부는 평균 8.82~9.52배의 차이가 있었다. 그리고 전용면적 $125{\sim}184m^2$에서는 방수공은 평균 1.89~2.07배, 보통인부는 평균 8.57~9.38배의 차이가 나타났다.

• 상하수도학회지
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• 제20권3호
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• pp.411-429
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• 2006

To improve Service quality for water and wastewater works, most water and wastewater utility effort to develop not only facility construction but also operation optimization. The operation is optimized by accurate estimation for ongoing situation. And from the accurate estimation, utility operator gain a information about their service quality and problems, So we developed a evaluation tool (Performance Indicators: PI) for service activity of water and wastewater works. The PI was developed in many countries and some international organizations (World Bank, IWA etc.) for service benchmarking. And ISO (international organization for standardization) just has been making a service standard for water and wastewater system (So called ISO/C224). This proceeding for making a service standard is ongoing now and will be launched in 2007. In our study, PI was composed of 6 parts (A human resource, facility management, operation, service quality, finance and environment). To evaluate water utilities, performance indicators for water was consisted of 100 items. Each 2 water utilities were estimated by this performance indicator. From the study, we just know that the performance indicator was a very useful tool to estimate utility service quality. And from the result, it is possible to know the strong and weak point of estimated utilities.

• 한국토양비료학회지
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• 제44권6호
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• pp.983-990
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• 2011

Universal Soil Loss Equation (USLE) has been used to estimate potential long-term soil erosion in the fields. However, the USLE does not estimate sediment yield due to lack of module considering sediment delivery ratio (SDR) for watershed application. For that reason, the Sediment Assessment Tool for Effective Erosion Control (SATEEC) system was developed and applied to compute the sediment yield at watershed scale. However, the R factor of current SATEEC Ver. 2.1 was estimated based on 5-day antecedent rainfall, it is not related with fundamental concept of R factor. To compute R factor accurately, the energy of rainfall strikes should be considered. In this study, the R module in the SATEEC system was enhanced using formulas of Williams, Foster, Cooley, CREAMS which could consider the energy of rainfall strikes. The enhanced SATEEC system ver. 2.2 was applied to the Imha watershed and monthly sediment yield was estimated. As a result of this study, the $R^2$ and NSE values are 0.591 and 0.573 for calibration period, and 0.927 and 0.911 for validation period, respectively. The results demonstrate the enhanced SATEEC System estimates the sediment yield suitably, and it could be used to establish the detailed environmental policy standard using USLE input dataset at watershed scale.

• Corrosion Science and Technology
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• 제8권6호
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• pp.243-250
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• 2009

When a steel sheet pipe applied to marine environment, an anti-corrosive coating should be treated to obtain long-term life-time for steels, especially, splash zone. Although anti-corrosive property of coatings is required to be tested in real marine environment, it is difficult because of long test time such as 20 years or more time. Therefore, we used cyclic corrosion tester in a laboratory, which has similar conditions with salt-dry-wet process such as real marine environment. Anti-corrosive properties of the coatings and two steels were tested their anti-corrosive properties under cyclic corrosion test conditions(KS D ISO 14993) and the results were compared with estimate life-time in real marine environment. According to cyclic corrosion test, accelerated corrosive factor of each anti-corrosive coating was investigated accelerated corrosive factor from impedance with EIS method. Accelerated corrosive factor of type SS400 carbon steel and A690 was also investigated their accelerated corrosive factor from the regression curves of weigh loss results. One of the anti-corrosive coatings showed about 50 years life-time compared with standard sample life-time. Carbon steel SS400 showed from 0.1 mm/yr to 0.06 mm/yr as its corrosion rate.

• 한국건축시공학회지
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• 제2권2호
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• pp.129-134
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• 2002

The strength and durability of concrete are affected by various factors such as the quality of material, mixing ratio, construction, the method of cure, time elapsed. the condition of test and etc., it is very difficult to pre-estimate the strength of concrete with the use of experimental specimen. The domestic standard of specimen cylindrical type and its sizes are both l0cm$\times$20cm and 15cm$\times$30cm, which are prescribed in KS F2405, and the loading speed is prescribed to test with 2~3kgf/$\textrm{cm}^2$ per second. The loading speed should have great effect on the compressive strength, but in reality in the construction site sometimes the loading speed is applied so dubiously that the value of the compressive strength can be unreliable. And the cross sectional area of a specimen should be level and smooth, otherwise it can be broken at a lower stress than the real strength through the eccentric or intensive working of the load. Capping should be carried out in order to measure the strength correctly. And used for capping are various materials such as capping compound, cement glue, plaster, mechanical grinding and etc. In this study, therefore, I have carried out an experiment on the relationship among the loading speed, the ratio of height to diameter of specimen, the method of capping, and the compressive strength, for the efficient quality control of concrete structures. So this study has been purposed to provide some basic data that can be used effectively at construction sites.

• Steel and Composite Structures
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• 제21권4호
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• pp.921-947
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• 2016

Concrete Filled Fibre Reinforced Polymer Tube (CFFT) for new columns construction has attracted significant research attention in recent years. The CFFT acts as a formwork for new columns and a barrier to corrosion accelerating agents. It significantly increases both the strength capacity (Strength enhancement ratio) and the ductility (Strain enhancement ratio) of reinforced concrete columns. In this study, based on predefined selection criteria, experimental investigation results of 134 circular CFFT columns under axial compression have been compiled and analysed from 599 CFFT specimens available in the literature. It has been observed that actual confinement ratio (expressed as a function of material properties of fibres, diameter of CFFT and compressive strength of concrete) has significant influence on the strength and ductility of circular CFFT columns. Design oriented models have been proposed to compute the strength and strain enhancement ratios of circular CFFT columns. The proposed strength and strain enhancement ratio models have significantly reduced Average Absolute Error (AAE), Mean Square Error (MSE), Relative Standard Error of Estimate (RSEE) and Standard Deviation (SD) as compared to other available strength and strain enhancement ratios of circular CFFT column models. The predictions of the proposed strength and strain enhancement ratio models match well with the experimental strength and strain enhancement ratios investigation results in the compiled database.

• Steel and Composite Structures
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• 제20권6호
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• pp.1369-1389
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• 2016

This paper investigates the flexural stiffness of simply supported steel-concrete composite I-beams under positive bending moment through combined experimental, numerical, and different standard methods. 14 composite beams are tested for experimental study and parameters including shear connection degree, transverse and longitudinal reinforcement ratios, loading way are also investigated. ABAQUS is employed to establish finite element (FE) models to simulate the flexural behavior of composite beams. The influences of a few key parameters, such as the shear connection degree, stud arrangement, stud diameter, beam length, loading way, on the flexural stiffness is also studied by parametric study. In addition, three widely used standard methods including GB, AISC, and British standards are used to estimate the flexural stiffness of the composite beams. The results are compared with the experimental and numerical results. The findings have provided comprehensive understanding of the flexural stiffness and the modelling of the composite beams. The results also indicate that GB 50017-2003 could provide better results in comparison to the other standards.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.331-340
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• 2009

This study is objected by suggesting rationalization method of management and maintenance cost for railway investment assessment. The estimate of rational benefit and cost are a work of vital importance to decide railway investment as preliminary feasibility investigation is institutionally reinforced since January 2007. In particular, railway management and maintenance cost have to be applied to realistic and detail cost as railway investment assessment guide. For example, types of railway, construction of new line, improvement of conventional line, double tracking, railway electrification. However, railway investment assessment is inconsistency because of estimating the railway management and maintenance cost using existing unrealistic management and maintenance cost. Therefore, this study is performed parametric analysis effecting on the railway management and maintenance cost considered new technique, enhanced facilities and improved standard. Also, it suggests the itemized standard management and maintenance cost. Finally, it will be helped to establish the base of railway investment through the rationalization method of management and maintenance cost.

• 한국주거학회논문집
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• 제26권2호
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• pp.21-28
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• 2015

The purpose of this paper is to estimate and deduct appropriate Hanok type within Suwon Hwaseong Fortress in which formula Hanok type has not remained. To do so, urban change according to chronology is analyzed and architectural aspect of transition is collected. By using geographic information in Suwon Hwaseong Fortress, present urban structural density, status of architecture and chronological aspect of transition in one-story buildings is surveyed. Through these data, appropriate Hanok form and density to the area is suggested. As a result, Hanok with two or more stories is economically suitable because its average plottage is excessively narrow. And back trowelling is desirable to construct walls in some concentrated areas with Hanok through arrangement of construction. Also in the other building sites, Hanoks are formed by a standard for separation to the property line. However it is necessary that exist standard about separation of property line is institutionally alleviated.

• 한국건설관리학회논문집
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• 제19권3호
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• pp.70-78
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• 2018

기후변화에 대한 우려가 커지면서 건설산업에서도 환경부하를 줄이기 위해 지속적으로 노력하고 있으며, 환경부하를 산정하기 위한 효과적인 방법론으로써 LCA (life cycle assessment)가 제시되고 있다. 그러나, LCA는 환경부하량 산정을 위해 작업에 투입되는 자원량에 대한 정보가 필요하기 때문에 이러한 정보의 확보가 어려운 초기 설계단계의 환경적 검토에는 활용되지 못하고 있다. 이 연구에서는 도로의 배수시설물을 대상으로 표준단면에 기반한 작업물량산출체계를 개발하고 환경부하량을 산출할 수 있는 모델에 활용하였다. 이 모델은 초기 설계단계의 가용정보만으로 LCA에 필요한 자원량을 산정함으로써 환경부하량을 산출할 수 있다. 모델의 유효성을 검증하기 위해 5개의 검증사례를 적용하였으며 원단위추정모델 및 회귀모델과 비교하였다. 그 결과 평균 9.94%의 절대오차율평균을 나타내 다른 모델보다 상대적으로 정확하며 초기 설계단계에서 사용할 수 있는 유효한 모델이라는 점이 확인되었다.