• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2013.11a
• /
• pp.72-73
• /
• 2013

In this paper, types of ready mixed concrete in construction site supported by different company has been researched. The practicability of the commercial available ready mixed concrete has been tested, and the standard deviation has been modified from Vc=Vo+3б to Vc=Vo+1.73б. Unnecessary premium rate has been cut and economical efficiency of the ready mixed concrete has been improved.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.5 no.4
• /
• pp.427-434
• /
• 2017

The generation of construction waste can be divided into a decommissioning phase and a new construction phase, and most of the waste is generated at the decommissioning stage. However, recently, domestic new construction construction has expanded to 150 trillion yards per year, so construction work is increasing rapidly. Especially, as the size of the construction work with much waste of construction waste exceeds 100 trillion, the management of the amount of construction waste in the new construction site is required. Unlike the dismantling work site, the new construction site can separate waste generated by each property, and relatively low foreign matter content is generated. The purpose of this study was to investigate the amount of construction waste generated by new construction sites and to calculate the unit amount of construction waste based on this. In addition, since the existing unit cost is centered on concrete and mixed waste, we set the basic unit by setting synthetic resin, waste wood, and waste board as additional items. The basic unit survey was carried out to investigate the wastes according to the characteristics of each construction period. As a result of the survey, the new construction site showed that most wastes were discharged in the first 30% and after 70% of the process, and the ratio of mixed construction waste was as high as 45%. As a result of this study, it was found that about twice as much waste was produced as compared with the conventional standard product.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.38 no.5
• /
• pp.721-731
• /
• 2018

Manpower in domestic construction sites is becoming more and more aging. Various methods have been devised to prevent productivity and quality deterioration of construction due to absence of skilled workers and difficulty in supplying manpower. Especially, many researchers study various methods such as Machine Guidance (MG) and Remote Machine Control to improve productivity and quality. Although many prior studies have been conducted since the advent of MG, There is lack of field test in a difficult site to stakeout. In this study, field test of MG excavator was carried out at difficult site to stakeout, and productivity analysis and quality evaluation were conducted. As a result of the analysis of productivity, the minimum value was 20.5%, the maximum value was 56.9%, and the average productivity in 4 days was 38.3% higher than the standard product. As a result of the analysis of quality, the horizontal error ${\pm}1cm$ and the vertical error ${\pm}2cm$ confirmed in the previous study were verified.

• Korean Journal of Construction Engineering and Management
• /
• v.7 no.5
• /
• pp.159-166
• /
• 2006

It was found that Korean Standard of Estimate which has been used as the only basis of cost estimate of public construction projects had some side effects such as jerry-build construction and over-estimation because it failed to reflect the current price and the state-of-the-art construction methods in a changing construction environment. Therefore, the government decided to gradually introduce historical construction cost into cost estimate of public construction projects from 2004. This paper presents analytic criteria and a process model for deducing more current and reasonable historical construction cost for contract items from not only previous contract prices but also all of the other bid prices that were not contracted. The procedure of estimating actual unit cost proposed in this paper focuses on the removal of abnormal values including strategically too low or high prices and the time correction. In addition, basic research is conducted for the correction of actual unit cost through the analysis of fluctuation of bid price depending on bidding types and rates of successful bid. It is anticipated that the effective use of the proposed process model for estimating actual unit cost would make the cost estimation more current and reasonable.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.12
• /
• pp.200-207
• /
• 2017

3D printing is making a huge difference to existing industries and is beginning to be applied in the field of construction. 3D printing construction differs from existing construction techniques. Therefore, new construction processes need to be developed. In particular, the accurate construction duration is linked directly to a successful project. A method for estimating the construction duration for 3D printing construction is necessary. In this study, a 3D printing construction process and duration estimation method were derived to prepare for the future introduction of 3D printing in construction. The scope of the study was assumed to be 3D printing equipment capable of pouring concrete, and limited to a frame structure construction. The developed construction period estimation method was applied to the virtual test model. As a result of applying the test model, the construction duration was shortened by approximately 50% compared to the existing construction technique. The method of estimating the construction period developed in this study can be applied to 3D printing constructions in the future and help establish a business plan.

• Journal of the Society of Disaster Information
• /
• v.8 no.4
• /
• pp.328-335
• /
• 2012

The resource-based estimating based on standard unit price of construction work was estimated by multiplying the price per standard unit of work on the amount of labor, material, equipment use time. However, limitation of the resource-based estimating way does not adequately reflect the actual transactions prices. On the subject of water tunnel excavation as a new attempt to overcome these limitations, this study analyzed productivity by work type into cutter inspection/ exchange, TBM maintenance, TBM inspection/refueling, subsequent installations, tramcar, operating change, a cave-underground reinforcement / rock reinforcement, safety / meetings and analyzed actual cost estimating and the net advance rate based on this analysis result. Actual cost estimating calculation approach presented in this study can be utilized as a useful tool to predict the actual cost estimating in the TBM water tunnels field.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.1
• /
• pp.293-303
• /
• 2014

Recent historical unit price is presented by the Korea Institute of Construction Technology (KICT) and it is analyzed by data from large-scale projects. Therefore it has problem applying to small-scale projects. To indicate the problem, the study compared historical unit price of large-case project and small-case project in the case of civil engineering work, building construction, and mechanical facility work. As a result, average historical unit price of small-scale project was 26.6% higher than large-scale project. On the other hand, difference on the labor cost was 18.4%, difference on material cost and overheads were 8.18%. Moreover, the study proposed compensation method to correct to apply recent historical unit price to small-scale project.

• Korean Journal of Construction Engineering and Management
• /
• v.6 no.5 s.27
• /
• pp.186-192
• /
• 2005

The purpose of this study is to find the reality of environmental management cost in construction projects and to suggest some policies in order that owners appropriate the environmental management cost reasonably in the construction budget for reducing the environmental pollution at job sites. We surveyed the actual state of appropriating and expending the environmental management cost over 122 construction sites. According to the results of the survey, while the appropriated rate of the environmental management cost was 0.59% of the total construction cost. the expended rate reached at 0.94%. When examining the antipollution facilities which were operated in job sites, the investment for equipment against air-pollution such as tire washer, dust-proof device was relatively higher than other antipollution equipment. As the method appropriating the environmental management cost, we concluded that a quantity-per-unit costing method is more reasonable than appropriating at a fixed rate of total construction cost considering that there is little correlation between total construction cost and the environmental management cost. To do so, antipollution facilities that must be examined at a design or estimation stage of a construction project should be prescribed by the law. Moreover, referenced cost data for the quantity-per-unit costing should be prepared and officially published.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.3
• /
• pp.1007-1015
• /
• 2014

The importance of construction waste reusing and recycling is becoming increasingly large because the demolition industry is in current trend to pursue for sustainable growth. As the considering situation of the domestic housing construction and existing house, a scale of demolition industry is expected to be increased continuously. But the related cost regulations that are used in tendering in the demolition industry are insufficient, also the computer system for estimating the demolition costs have not been developed yet. Therefore, in this study suggests man-hours of 21EA items which are utilized to estimate demolition cost and work rate of $1.0m^3$ breaker which is used mostly in domestic demolition industry after analyzing a case study for deconstruction works. The computer system is developed for the estimating demolition cost easily, which are including five modules such as a project information, a unit cost management, a standard unit cost table, a bill of quantity, and a reporting system. This computer system is possible to apply for estimating cost of both mechanical demolition and blasting demolition. The biggest advantage of this system is to estimate cost to utilize standard WBS which is linked with standard unit table and each DB. This can help unskilled users use easily for it.

• Korean Journal of Construction Engineering and Management
• /
• v.24 no.3
• /
• pp.12-19
• /
• 2023

In the case of the construction industry, the relationship between process and cost should be appropriately distributed so that the finished product can be delivered at the minimum fee within the construction period. At that time, it should be considered the size of the bridge, the construction method, the environment and production capacity of the factory, and the transport distance. However, due to various reasons that occur during the construction period, problems such as construction delay, construction cost increase, and quality and reliability degradation occur. Therefore, a systematic and scientific construction technique and process management technology are needed to break away from the conventional method. The prefab(Pre-Fabrication) is a representative OSC (Off-Site Construction) method manufactured in a factory and constructed onsite. This study develops a resource and process plan optimization system for the process management of the Nodular girder, a prefab bridge girder. A simulation algorithm develops to automatically test various variables in the personnel equipment mobilization plan to derive the optimal value. And, the algorithm was applied to the Paju-Pocheon Expressway Construction (Section 3) Dohwa 4 Bridge under construction, and the results compare. Based on construction work standard product calculation, actual input manpower, equipment type, and quantity were applied to the Activity Card, and the amount of work by quantity counting, resource planning, and resource requirements was reflected. In the future, we plan to improve the accuracy of the program by applying forecasting techniques including various field data.