• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1350-1357
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• 2010

In tunnelling, temporary ventilation is very important factor in the safety of worker and the work efficiency which is affected by visibility. There are a lot of problems in the recent tunnel construction, because the longer the tunnel, the more the present design doesn't satisfy the allowable standard about dust and air pollution. Especially, In case the length of tunnel is more than 1,000m, the ventilation efficiency tends to decrease. In this study, the field measurement of the degree of contamination was performed near the face of tunnel. Based on the results obtained, the main factors of problem in temporary ventilation are the difference of temperature between outside and inside, the rate of leakage of ventilation duct and the dust and so on. It maybe helpful to the solution of problems, and also the accurate ventilation estimate.

• KIEAE Journal
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• v.14 no.5
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• pp.21-28
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• 2014

To improve environmental problem as globally climate changes, domestic and foreign government have been trying to reduce green gas emitted by all industries. With making the green building certification system that assess the substantiality and energy performance of building, a governments have been using by a way for reducing green gas emitted in building industry. G-SEED(Green Standard for Energy & Environmental Design) developed in Korea have been reinforcing, and a number of projects certifying the G-SEED have been increasing continuously. As a demand of G-SEED certification is rising, a question on the additional cost data as certifying G-SEED is rising. It is because additional cost as getting the certification is important fact for G-SEED level decision and whether getting the certification or not. Therefore, this study analyzed additional construction cost as certifying G-SEED through performance improvement and design change of general office building not to get G-SEED. In conclusion, an additional construction cost ratio of G-SEED projects to the reference building is drawn as certified level; +0.26%, silver level; +2.29%, gold level; +3.89%, and platinum level; +5.48%.

• KIEAE Journal
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• v.17 no.5
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• pp.87-94
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• 2017

Purpose: Prefabricated modular space such as a container construction has recently been interested unlike the conventional construction method, and their scale have expanded from small buildings such as cafes, houses and pensions to shopping centers, complex cultural spaces where shows and exhibitions are possible doing. In this way, the container is in the spotlight as an advantage such as mobility, flexibility, correspondence, economic efficiency, recyclability and so on. However, there are no specific guidelines and standard design methods in aspects of structural calculation, functional insulation and environmental configuration. Therefore, as the first step to resolve these problems, this study has focused on the field of environmental performance of container construction, presented appropriate guidelines and searched ways to improve performances. Method: For this study, seven types of the modular building were chosen and compared, and their energy performances have been analyzed using a proven simulation tool. Essential methodology and terminology were examined to estimate and judge their efficiency. Result: In conclusion, energy performances depend on specific configuration of combined unit spaces, and design guidelines cold be set up for promoting their use in the practical field.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.10
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• pp.225-234
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• 2019

The purpose of this paper is to analyze the additional construction cost of G-SEED certification for domestic office building reflecting the latest standard(G-SEED 2016-2), and to derive cost impact by category and level. Therefore, it is intended to provide quantitave cost data according to G-SEED certification at the planning phase of the project, estimate the additional construction cost per level according to G-SEED Certification of similar project to be carried out in the future, and encourage G-SEED certification by supporting the decision of the owners. Method: The Process and method of this study are summarized in five steps, 1) Review of previous research, 2) Selection of target project, 3) Scenario setting by level, 4) Additional construction cost for each evaluation category, 5) Extraction of additional construction cost ratio by level. Result: This paper analyzed the cost impact by deriving the additional construction cost of detailed category for level improvement according to the revised G-SEED certification(G-SEED 2016-2). In conclusion, an additional construction cost(ratio) of G-SEED projects to the reference building is drawn as good level; 157,426,241 KWN(+0.43%), very good level; 321,907,802 KWN(+0.88%), excellent level; 999,371,478 KWN(+2.74%), and outstanding level; 1,467,047,718 KWN(+4.02%).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.5
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• pp.1199-1208
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• 1994

In the country, supervision cost is being estimated by percentages of construction cost or cost plus a fixed fee without a reasonable standard. This type has no function for adjusting supervision cost according to variables, such as construction work complexity, extent of supervisory services, fluctuations in prices. In this study, an objective criterion to estimate supervision cost with improved supervisory services has been developed, in which adjusting functions as stated above should be properly considered. A comparative study of supervisory service systems in foreign countries and a survey through questionnaire were carried out for the study. An objective criterion from the results is proposed in the form of an expression or table.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1D
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• pp.67-72
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• 2008

Heavy equipment is a very important factor for successful construction implementation. Also, the cost for heavy equipment is a major part of construction cost. Therefore, the estimation of equipment cost is a critical job in the construction planning phase. A formula for production rates shown in 'Standard Unit Labor' has been used to estimate construction equipment capability per hour and cost. Although the performance of equipment has been improved, the efficiency rates in the formula are not updated lately. Therefore, this research performed several site visits to measure construction equipment working time and then calculates the efficiency rates for hydraulic backhoe, loader, and dump truck. The results show that the measured efficiencies of backhoe and loader are higher than current ones and vice versa for dump truck. This research proposes the needs for a standardized calculation formula and systematic and long-term data collection and measurement for updating efficiency rates for heavy equipment.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.4
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• pp.20-36
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• 2022

This study aims to provide basic data for high-quality street tree management by setting reasonable management items and appropriate unit prices by reviewing the adequacy of current street tree management. Currently, street tree management items, except for street tree pruning, use general landscape tree quantity per unit for the street tree management quantity per unit. KEPCO (Korea Electric Power Corporation) applied pruning items from standard electric production infrastructure and carried out the activities at an average unit price of 51% lower for heavy pruning and 39% lower for light pruning than the standard estimate. This was judged to be a level that could not maintain or increase the quality of street tree management. It was determined that an appropriate standard unit price for street tree management was necessary. To improve the quantity per unit for the proper management of street trees, it was necessary to review costs in the field. However, due to the absence of data on actual construction costs in the domestic landscape field, detailed items of the US RSMeans Building Construction Cost Data (RSMeans) were reviewed, and the actual construction costs were calculated by applying personal domestic expenses. As a result, the standard of the estimated unit showed a good ratio of 107% for heavy pruning of street tree pruning compared to the actual construction cost, but light pruning was underestimated with a 59% ratio. Shrub pruning was 82%, weeding was 92%, tree fertilization was 87%, and windbreak wall installation was 91% under-engineered. In addition, it was also confirmed that the watering by sprinkler trucks and chemical spraying were over-designed compared to the actual construction cost at the rates of 118% and 124%, respectively. Due to the specificity of the street trees, the increase in personal expenses and the input cost of equipment, such as road safety controls, were judged to be the main cause of the underestimation of items. Therefore, it is necessary to add items related to street trees and general landscape trees to the landscape maintenance items of the standard of the estimated unit.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.705-716
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• 2017

As many environmental pollution problems have arisen, various studies related to the environmental evaluation have been carried out in the construction industry. However, there is no methodology for estimating the environmental load quickly for design alternatives of civil facilities in the design phase. This study aim to establish criteria of works information and designed parts which can efficiently estimate environmental loads of PSC beam bridge based on standard quantity at the early design phase. For this purpose, a detailed environmental loads database was constructed by performing Life Cycle Assessment (LCA) based on detailed design data of 25 bridges. In addition, major work with high impact on environmental load were selected, and the analysis of characteristics of environmental load according to the required materials and 8 impact categories were conducted. As a result, the superstructure accounted for 42.91%. In the superstructure, remicon of the material base and PSC beam work occupied 53.13% and 31.25%. In the substructure, remicon, rebar, and cement, which are material base, accounted for more than 93%. It is expected that this major work and material information for each part of bridge can be utilized in the construction of the model, which can estimate the approximate environmental load, reflecting the characteristics of the structure in the design phase.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.1
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• pp.110-115
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• 2002

The tunnels built in recent years are equipped with traffic counters and pollution sensors (mostly, CO and Vl sensors). Utilizing these built-in sensors, it is possible to develop an algorithm to estimate the amount of pollutants exhausted from the each class of cars passing through the tunnel. These estimated data can be effectively utilized not only for ventilation control but also for designing ventilation facilities. The diffusion of pollutants in a tunnel can be described with one-dimensional diffusion-convection equation. This equation is approximated with interpolation functions and weighted residual method converting to adequate form for standard state estimate algorithms. With this converted equations, a least square optimization based algorithm is developed, whose outputs are the estimated amounts of pollutants emitted from each class of cars. In order to verify the feasibility of the developed algorithms, simulations are performed with the real data acquisitioned from the Tunnae tunnel located in Young-Dong highway in Korea.

• Korean Journal of Construction Engineering and Management
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• v.6 no.4 s.26
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• pp.152-163
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• 2005

Pile driving work causes a vibration problem in the construction site using pile foundation and often causes civil affairs by construction noise around the construction site. For the vibration and noise problems, the driving after drilling method rather than the direct driving method is being generalized for reducing vibration and noise. However, this method also causes civil affairs when the driving work is operated in adjacent area. This study suggests a criterion for evaluating an optimal allowed distance for pile driving work by the driving after drilling method. Actual surveys of vibration and noise for pile driving work in seven construction sites were used for developing regression analysis equations. The results can be a standard to estimate the allowed distance to avoid vibration and noise problems in pile driving work for deep foundation.