• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.279-284
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• 2001

The owner's evaluation system about the contractor's work performance is used to give the contractor some advantages or disadvantages. According to the result of evaluation of the contractor's performance in the given construction project, the owner identify the good contractors and give them some merits in the future project bidding. However, the system used in the Korean construction industry has caused many problems and has been operated improperly. As a case study, this paper investigates the current problems existed in the KNHC (Korean National Housing Corporation) evaluation system and suggests some directions for its efficient operation. In doing so, the study performed interviews with the KNHC officers and the related contractors, using a structured questionnaire

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.913-921
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• 2019

The government introduced the comprehensive evaluation bidding system with the goal of pursuing the best value and the global standard in 2016. However, for the evaluation criteria on the construction evaluation reflected to the comprehensive evaluation bidding system, the problems of the objectivity insufficiency, the inclusion of multiple subjective evaluation items, and the irrationality of the weight for each evaluation item are continue to be presented. The central office group, the local government, the relevant industry, and the expert group share recognition, but the solution is not derived. Hence, the major evaluation items to be improved were derived with the characteristics analyzed to secure the objectivity of the construction evaluation. For the analysis method, the standard deviation and the Fleiss Kappa analysis method were used by utilizing the characteristics that the construction evaluation criteria consist of all 4-point measures (good, average, insufficient, and poor). According to the result, the 10 evaluation items of the total 25 construction evaluation items were derived as the evaluation items to be improved. It was found in the analysis on the major characteristics of the derived evaluation items that the qualitative evaluation criteria such as 'Very Suitable' and 'Suitable' were commonly included in the detailed evaluation guidelines. Hence, as far as the future construction evaluation standards are concerned, the qualitative evaluation standards are sublated, and the improvement should be made mainly for the quantitative evaluation criteria enabling the objectivity assurance.

• Tunnel and Underground Space
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• v.5 no.4
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• pp.297-307
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• 1995

터널은 긴 선상구조물로서 사정조사결과와 다른 지질조건이 나타날 수 있으므로, 안전하고 합리적인 터널공사를 위해서는 시공중 지질조건에 적합한 지보설계를 실시하는 것이 필수적이다. 이를 위해서는 시공중 터널주변자반에 대한 정량적이고 공학적인 평가가 매우 중요하다. 그러나 시공중 암반을 평가하는 것은 매우 어렵고 조사자의 경험과 지식의 차이에 의해 평가정도가 크게 달라져 그 불합리성이 심화되고 있는 실정으로 터널주변암반에 대한 합리적인 평가방법이 절실히 요구되고 있다. 본 연구에서는 터널화상처리, GeoCAD, 역해석으로 구성된 평기시스템을 개발하였다. 본 시스템은 터널막장에서의 조사.시험 및 화상처리기법을 통하여 암반분류.평가를 실시하고, 터널주변 지반구조 및 굴착/지보과정의 3차원 모델링을 통하여 전방지질을 예측가능하게 하며, 터널계측자료의 역해석을 통하여 터널주변 지반의 물성을 정량적으로 평가할 수 있는 체계적이고 종합적인 평가시스템이다. 또한 이를 NATM 공법으로 시공되는 터널현장에 적용하므로써 본 시스템의 현장적용성을 검증하였으며, 이를 통해 적절한 지보공을 시공하여 터널의 안정성을 확보하고 합리적인 시공관리를 달성할 수 있었다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.568-571
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• 2008

To help a owner selecting proper contractors about the specified contract, the Evaluation and Public Announcing System of the Contractor's Construction Capacity has been introduced since 1997. But, the system has been done violence to its original meaning and purpose as time went on. When annually announcing the Contractor's Construction Capacity, especially, there was frequently a large range of opinion on the issues. On that account, MLTM(Ministry of Land, Transport and Maritime Affairs) has had to make a alteration to improve those and is making efforts for a constructive policy now. The purpose of this paper is to conduct a basis study on the Integrated System after reflecting points to be considered about improvements and the current of the times.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 1995.03a
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• pp.213-219
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• 1995

터널굴착중 막장조사관찰은 막장의 안전성, 암질판정, 풍화 및 변질정도, 용수상태, 절리의 특성을 파악함으로써 시공의 합리성을 달성할 수 있는 매우 중요한 조사항목이다. 그러나 이러한 작업은 시공상 시간적제약을 받고, 조사자의 경험과 지식의 부족으로 암반에 대한 공학적 평가가 부족한 실정이다. 이러한 문제점을 극복하고, 지반조건변화에 능동적으로 대응한 터널시공을 위해서는 정확한 암반평가가 필수적이라 할 수 있다. (중략)

• Korean Journal of Construction Engineering and Management
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• v.19 no.2
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• pp.3-14
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• 2018

The system to appraise the execution capabilities of construction companies had been began as the Construction Contract Restriction System in 1958, was changed as the Construction Subcontract Restriction System in 1961, and finally has been operated as the Appraisal and Public Announcement of Execution Capacity (APAEC) from 1996. The APAEC system has been utilized as a firm and unique tool for assessing the execution capacities of construction companies despite many problems and continuous system changes. In spite of numerous studies to improve the APAEC system, however, efforts to analyze the system from the empirical point of view were insufficient. In this study, we analyze the status of APAEC system through analyzing correlations among assessment results of the APAEC, earned values of construction works, construction management performance indexes, and macroeconomic indexes for the past 10 years from 2007 to 2016. As a result of the analysis, it was found that Appraisal Value of Execution Capacity (AVEC) is excessively inflated in engineering and landscaping areas compared to Earned Value of Construction Work (EVCW) and the correlations between the AVECs and EVECs are not high in the areas of engineering, industrial equipment, and landscaping. In addition, technical appraisal values are excessively inflated in engineering and landscaping areas and correlations between AVEC and its components are high in the areas of engineering & building, industrial equipment, and large companies, but low in the areas of engineering, building, landscaping, and small and medium companies. Finally, the concentration of the AVEC is intensifying more and more and the concentration deteriorates construction management performance indexes and macroeconomic indexes. If we continuously improve the APAEC system based on the implications derived in this study, the APAEC system will be able to maintain it's position of a firm and unique means to access the execution capacities of construction companies.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3A
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• pp.181-188
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• 2009

This study presented the basic data for determining reasonable construction method and evaluating the structural safety of suspension bridges. The analytical program was developed to conduct initial shape and natural frequency analysis, construction stage analysis and reliability analysis considering construction sequences. This program was based on analysis models of suspension bridges and reliability theories used in the previous study. A construction method was established considering various construction variables such as construction order and construction direction of girder and synchronized construction of main and side span etc. The dynamic construction analysis by a construction scheme was conducted with the developed program. Benefits of the characteristic analysis by the construction scheme was presented estimating structural response of critical members respectively. Structural reliability analysis by construction stage was conducted considering aleatory uncertainties. The safety of suspension bridges by established construction method was quantitatively estimated using reliability index and failure probability. Analytical results were re-estimated considering epistemic uncertainties, and critical percentile distributions of risk at the construction stage were presented using the frequency histogram.

• Journal of the Korea Institute of Building Construction
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• v.10 no.1
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• pp.181-191
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• 2010

Lightweight panels are currently used in many ways, such as inner walls of the skyscrapers and residential buildings in Korea. Moreover there has been an increasing of interest in developing construction method and quality improvement as many buildings became higher, because there are more advantages like constructability, finishability, and economic efficiency, etc. than previous heavy weight concrete wall. It is necessary to analyze the characteristics and evaluate the performance of lightweight panels when selecting proper methods and materials to building characteristics and builder's demand. However, there doesn't exist systematic data with a classification of lightweight panels' type and performance. The purpose of this study is to classify domestic lightweight panels by both type of exterior board and construction method, and also to evaluate each performance by surveying user's opinion.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2A
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• pp.93-102
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• 2010

The numerical analysis and safety assessment by construction stages were considered the essential examination particular in order to solving the unstability of long-span bridges in the middle a construction. When estimating structural response characteristics by the construction stage analysis of long-span bridges, the influence of the near-field ground motion (NFGM) would be evaluated as a critical factor for the seismic design because it indicates clearly different aspects from the existing input earthquake motion data. Therefore, this study re-examined the response aspect of long-span bridges considering NFGM characteristics based on the response spectrum result, and advanced the presented numerical analysis program by the related research for conducting the construction stage analysis and reliability assessment of long-span bridges efficiently. The excellency of various construction schemes was assessed using the time history analysis result of critical member considering NFGM characteristics. For evaluating quantitative safety level, the reliability analysis was conducted considering the influence of external uncertainties included in random variables, and presented the safety index and failure probability of the critical construction stage by NFGM characteristics. In addition, the reliability result was examined the influence of internal uncertainties using monte carlo simulation (MCS), and assessed the distribution aspect of the essential analysis result. It is expected that this study will provide the basic information for the construction safety improvement when performing seismic design of long-span bridges considering NFGM characteristics.

• Journal of the Korea Institute of Building Construction
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• v.21 no.1
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• pp.11-19
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• 2021

The aim of the research is providing a fundamental data on quality and constructability of direct tile setting method depending on various cement to sand ratio for tiling dry cement mortar. A large number of tile setting failures reported is related with the cement mortar and its construction for tiling. Because of different materials of tiles, the properties of tiling dry cement mortar, an adhesive for tiling, can influence on quality and constructability of tiling differently. Practically, the easiest way of controlling the properties of the tiling dry cement mortar is to control the proportion of cement and sand. Hence, in this research, sand to cement ratio (S/C) was controlled. Since there is no standarized method on evaluating performance of dry cement mortar for tiling, a several sensory evaluation methods were suggested and executed. According to the experiments conducted in this research, the adhesive performance of cement mortar for tiles can be different depending on the sides such as tile and substrate. Additionally, depending on S/C, finishability, initial adhesive performance, and tile shifting resistance can be changed for ceramic tile. Therefore, under the conditions of this research, about 5 of S/C can be recommended for appropriate performace of tiling dry cement mortar.