• The Journal of Engineering Geology
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• v.17 no.1 s.50
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• pp.89-99
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• 2007

This paper intends to introduce more objective and qualitative rock mass classification method easily applicable to the excavation of gneissic masses showing corestone weathering profiles. It is proven that corestone weathering profile could be divided with reasonable accuracy into digging, ripping and blasting layers using visual and simple mechanical techniques such as Schmidt hammer rebound test on cut slopes, taking into consideration strength and spacial distribution of corestone, workability and work efficiency of excavation. Also, seismic refraction surveys were employed for shallow investigations (down to $20{\sim}30m$ depth) in corestone weathering profile and conducted across the top of vertical exposures where the underlying geology could be directly inspected. Some discrepancies ($3{\sim}4m$ in average and 6 m occasionally) between the actual and assumed materials with respect to seismic velocities were observed. Thus it can be concluded that field geotechnical mapping and field seismic test should be used together in order to get a relatively good accuracy in assessing likely excavation conditions of corestone weather-ing profiles.

• Korean Journal of Construction Engineering and Management
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• v.13 no.1
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• pp.3-13
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• 2012

The importance of project performance management as an alternative for solving problems is rising, which are followed by the hardships of managing construction project in the construction industry. This research classifies and applies the improvements made by the operator's work, in order to apply factors of success on the construction project, as performance management factors. In addition, in order to predict the results reflecting the project characteristic of performance management factor un-improvable by the operator in the initial stage of construction, the effect of project characteristic to the performance was drawn by performance difficulty. Also, in order to improve the predicted performance, researches on setting valid best practices according to the performance territory through a correlation analysis between the best practices improvable through the operator's work, and the performance was made.

• Korean Journal of Construction Engineering and Management
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• v.11 no.3
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• pp.115-124
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• 2010

Along with the recent economic downturn, domestic construction companies have also faced with many difficulties and obstacles. To overcome this situations, now they are trying to continuous efforts to improve efficiency and productivity of project performance through many means including the reduction of fixed cost expenditures. Level of work performance of construction field managers is very important factor of productivity improvement for successive performance of construction project. This study attempts to analyse level and influence factors for work performance of field managers in construction companies through analysis of work burden and level of work performance. Also this study attempts to present basic data of the improvement directions for enhancing construction efficiency and productivity in future.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.27-28
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• 2022

There is a limit to preventing various types of safety accidents in advance at construction sites. Even for buildings of the same total floor area, it is expected that the more complex the building shape or the higher the number of floors, the higher the probability of a safety accident. Therefore, it is necessary to analyze the effect of the shape of a building on safety accidents using safety accident data generated during actual construction. The purpose of this study is to analyze the impact of building shape on safety accidents. As a result, the R2 value of shape factor and safety accident was 0.901, and the R2 value of construction difficulty and safety accident was 0.944. In the future, the results of this study will be used as basic data for improving safety management related systems.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2017.11a
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• pp.257-259
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• 2017

최근에 국내에서 입법된 "지하안전관리에 관한 특별법"의 지하안전영향평가 등에서 지하매설물 및 굴착공사 관리의 중요성을 강조하고 있지만, 아직까지는 지하를 개발함에 있어 지반의 안전과 관련된 사항은 미흡한 실정으로 도심지 지반침하( Sinkhole) 현상이 매년 증가하고 있다. 그리고 지반침하(Sinkhole)는 발생이 될 경우 인명피해는 물론 도로나 주변 건물들에 막대한 피해를 줄 수 있는 소지가 충분한 대상으로 사료됨에도 불구하고 이러한 현상을 건설현장에서 심각하게 받아들이는 분위기는 어느 곳에서도 감지되지 않는다. 다만 정부부처나 공공기관에서 국회차원의 지대한 관심에 부응하여 이에 대해 광범위한 연구와 조사에 막대한 예산을 투입하여 다방면에서 진행되고 있는 것으로 파악되고 있다. 또한 이러한 연구결과의 자료를 근거로 하여 지반침하 사고의 주요 원인을 조사해본 결과 상하수도관 손상과 무리한 인접굴착공사 및 대부분의 대형건축공사 현장에 채택되고 있는 부력방지 대책의 일환인 영구배수공법의 무분별한 적용을 들 수 있었다. 이러한 상황에서 그 중 비용과 난이도를 고려현장에서 용이하게 저감할 수 있는 방법인 영구배수공법을 선정하여 영구배수공법의 이론적 고찰과 공학적 타당성(구조체 부상방지 안전성 검토기준)을 연구하여 무분별한 영구배수공법 적용으로 지반침하(Sinkhole)가 발생하는 것을 막아 인명피해와 도로나 구조물의 안전성을 확보하고 나아가 영구배수공법 적용으로 항구적 발생하는 천문학적인 유지관리비의 절감이 목적이다.

• Korean Journal of Construction Engineering and Management
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• v.21 no.6
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• pp.66-74
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• 2020

To prevent incident of demolition work the Building Management Act was implemented to manage demolition work. According to this law, buildings with the scale upper than 500㎡ of floor area are classified as permission to conduct the demolition work, however it may be hard to perform safety management at demolition work. In addition, the risk level of demolition work is varied with related to the structure type. So, the purpose of this study is to suggest the improvements of criteria on demolition work considering building structure types including small-scale structures such as masonry, wooden, and other structure. The research process was conducted by three steps. (I) Application of Building Management Act; (II) Analysis of demolition work by structure types; and (III) Subdivision of permission targets by building structure types. The result of this study, permission ratio was only 10% for total demolition work and 2.43% for masonry. Because the masonry, wooden, and other structure types are concentrated on a floor area of small-scale, the separate criteria of demolition work is need to prevent the accident and fatal incident. Through the results, the decision maker can be utilized (1) For the special building structure types, the criteria of enhanced safety management are applied by referring to the overseas law ; and (2) The demolition work can be considered by the criteria of separate permission in terms of structure types.

• Korean Journal of Construction Engineering and Management
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• v.21 no.4
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• pp.21-29
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• 2020

This study analyzed problems of operating performance bond for public works and derived some suggestions for improvement. The Contract Law for Government Owner requires to submit performance bond which guarantees performing the construction contractor pays back compensation money when the obligation is not executed. Currently, first bid eligibility for participation is exactly required for executing company of performance bond obligation, not considering volume, technical level, and special type of remaining works. In collaboration contract, if guarantee accident occurs, it is obliged for remaining collaboration contractors to be qualified to fulfill the whole contract. This study proposes following improvement plan to solve problems of current performance bone in public works. Firstly, qualification criteria must be deregulated exceptionally for selecting proper contractor, which executing performance bond obligation, considering progress and characteristics of remaining works. Secondly, In collaboration contract, the prerequisite of remaining contractors' should be deregulated as 'implementation requirement of the remaining works'from'implementation requirement of the whole work'. Finally, defect responsibility should be included in liabilities of performance bond by specifying that owner or guarantee agency bear them.

• Korean Journal of Construction Engineering and Management
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• v.23 no.1
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• pp.89-97
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• 2022

Recently, various problems such as reduced productivity, insufficient inflow of skilled manpower, reduced quality, and concerns about increasing safety accidents have appeared in the domestic construction industry. Stakeholder of construction project are considering the Off-Site Construction (OSC) method rather than the conventional on-site construction as an alternative. Despite the importance of decision making in the early stage of the adoption of OSC, there is a lack of methodologies for rational decision making. In this study, a decision making system has been developed to derive the final construction cost score by deriving the project characteristics, selecting the construction difficulty index, and developing a cost model for each construction method alternatives to calculate the standard construction cost. Using this system, the OSC method can be effectively evaluated in terms of its feasibility in the early stage of construction

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.468-477
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• 2019

This study analyzed the major contents and results of revision through an analysis of the specifications and the field survey to revise the construction cost calculation criteria. The result of the survey found that the background processing difficulty was reduced due to an improvement of the quality level of the field floor, and the enhancement of the material's function brought a decrease in construction time and the application of various construction methods. In addition, the application of combined waterproofing methods using more than one material was increasing and the productivity differed according to the site and location. Based on these results, waterproof items were subdivided and applied to the composite construction method, and the input items were differentiated according to the material and construction method. The adequacy of the construction calculation criteria was ensured by presenting the criteria classified according to the construction area, and deleting the items that are not applicable and amending them to make them suitable for the specifications by reflecting the actual conditions of the construction on the site.

• Korean Journal of Construction Engineering and Management
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• v.23 no.5
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• pp.77-86
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• 2022

Safety accidents on the construction scene can cause serious accidents, that take worker's life, and as the government has been making great efforts to reduce industrial accidents, the role of safety managers closely related to accidents at construction sites is becoming important. However, job stress is high due to excessive workload and inefficient work managed by safety managers in the current construction safety management system. So, it is necessary to improve and simplify the work contents. The main purpose of this study is to identify and improve tasks that need improvement and simplification of inefficient tasks, obtained through expert opinions and surveys on the level of difficulty and prevention effect of tasks in the safety manager's working stage, by using 2×2 Matrix analysis techniques. Therefore, this study will ultimately contributes reducing the occurrence of safety accidents on the construction scene.