• Title/Summary/Keyword: construction delays

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A Preliminary Study of the Development of DNN-Based Prediction Model for Quality Management (DNN을 활용한 건설현장 품질관리 시스템 개발을 위한 기초연구)

  • Suk, Janghwan;Kwon, Woobin;Lee, Hak-Ju;Lee, Chanwoo;Cho, Hunhee
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.11a
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    • pp.223-224
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    • 2022
  • The occurrence of defect, one of the major risk elements, gives rise to construction delays and additional costs. Although construction companies generally prefer to use a method of identifying and classifying the causes of defects, a system for predicting the rise of defects becomes important matter to reduce this harmful issue. However, the currently used methods are kinds of reactive systems that are focused on the defects which occurred already, and there are few studies on the occurrence of defects with prediction systems. This paper is about preliminary study on the development of judgemental algorithm that informs us whether additional works related to defect issue are needed or not. Among machine learning techniques, deep neural network was utilized as prediction model which is a major component of algorithm. It is the most suitable model to be applied to the algorithm when there are 8 hidden layers and the average number of nodes in each hidden layer is 70. Ultimately, the algorithm can identify and defects that may arise in later and contribute to minimize defect frequency.

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The research of Economical Re-oder point Estimating Method for building construction on the Downtown Area (도심지 건설공사 건설 자재의 효율적 재주문시점 산정 방안에 관한 연구)

  • Yun, Jung-Suk;Kim, Geun-Hwan;Jo, Young-Sik;Kim, Chang-Duk
    • KIEAE Journal
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    • v.13 no.1
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    • pp.159-165
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    • 2013
  • Recently buildings are being constructed on the downtown area. In most building construction sites on the downtown area, the need for adequate material inventories are critical in order to avoid project delays and cost increases due to inappropriate deliveries of key materials. However immoderate material inventories cause increasing inventory cost. Therefore, we need a proper management material inventories. This research re-establishes the existing safety stock and analyzes relationship between safety stock and service level. It suggests an economical re-order point based on safety stock considering service level, various demand and delivery time.

Basic study about Automatic Rebar Quantity Estimation Integrated with Structural Design Information (구조설계정보 통합 관리에 의한 철근 물량 산출 자동화 기초 연구)

  • Sung, Soojin;Lim, Chaeyeon;Kim, Sunkuk
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2015.05a
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    • pp.109-110
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    • 2015
  • Estimation of rebar quantity may be used as an index to evaluate the economic feasibility of structural designs. However, when using the software to estimate the rebar quantity, there may be some limitations such as data loss caused by human errors and estimation delays caused by increased input time, since the information on arrangement of rebar is inserted manually. To solve the problems of such quantity estimation software, it is necessary to develop a method on automatic input/output of structural design information for quantity estimation and an algorithm for accurate estimation of rebar quantity. The purpose of this study is to improve the existing rebar quantity estimation by connecting with the database on information related to rebar estimation and the algorithm for rebar estimation, in order to develop an algorithm to estimate an accurate, net rebar quantity. The study result can be used as basic data for development of software for efficient structural designs and automatic framework estimation of buildings.

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Insulation Property of Cement-based Non-combustible Inorganic Insulation Using MgO and Redispersible Polymer Powder (산화마그네슘 및 재유화형 분말수지를 사용한 시멘트계 불연단열재의 단열특성)

  • Son, Bae-Geun;Song, Hun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2021.05a
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    • pp.120-121
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    • 2021
  • The organic insulation material has excellent thermal insulation property, but it is difficult to expect fire stability, and semi inorganic insulation only delays combustible hour but it is difficult to expect fire stability. In this study, thermal insulation property of cement-based non-combustible inorganic insulation using cement and non combustible materials and redispersible polymer powder was studied. As a result of the experiment, the thermal insulation property decreased as the use of redispersible polymer powder increased, but the heat insulation property improved when using the appropriate amount.

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A Study on Sodium Sulfate Activited the Hydration Properties of Fly Ash-cement Paste (황산염나트륨 자극제를 사용한 플라이 애쉬 혼입 시멘트 페이스트의 초기 수화 특성에 관한 기초적 연구)

  • Wang, Zihao;Sun, Yang;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2021.05a
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    • pp.129-130
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    • 2021
  • In order to solve the problem of low early-age compressive strength of high volume fly ash concrete. This paper studies the effect of 2% sodium sulfate (Na2SO4) as a chemical activator on the paste with 40% fly ash content and a water-binder ratio of 0.30. The results indicate that the addition of Na2SO4 can effectively improve the early-age compressive strength of the fly ash-cement system, and the strength improvement rate on the first day reached nearly 70%. In addition, calorimetric analysis reveals that the incorporation of Na2SO4 promotes the early hydration of cement and fly ash, increases the cumulative hydration heat and delays the heat peak of the aluminum phase.

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PROJECT COMPLEXITY AS A MODERATOR OF PERFORMANCE BIAS TOWARDS OVERRUN

  • Li liu;Andrew Nguyen;James Arvanitakis
    • International conference on construction engineering and project management
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    • 2011.02a
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    • pp.38-45
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    • 2011
  • Studies have shown that infrastructure projects have continued to experience significant delays and cost overrun over an extended period of time and no evidence of learning ever have happened [1] [2]. Various causes contribute to the bias towards overrun [3]. This study contributes to literature by developing and subsequently validating a set of hypothesized relationships between project complexity and project performance. The results show that project complexity is associated with both the magnitude and variance of overrun. Further, the extent and magnitude of the positive bias towards overrun are moderated by project complexity.

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A Correlation Analysis of Influence Factors of Nonconformity in Construction Projects (건설프로젝트의 품질결함의 발생요인간 상관분석)

  • Chi, Sungjoon;Cha, Yongwoon;Han, Sangwon
    • Korean Journal of Construction Engineering and Management
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    • v.16 no.2
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    • pp.21-28
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    • 2015
  • Construction defects are major components that result in cost overruns and schedule delays in construction projects. There have been extensive research efforts to investigate the cause of defects. However, little effort has been devoted to analyze correlation among various reasons of construction defects while a defect is not usually an outcome of a single cause, but rather occurs when several interrelated causes combine. Based on this recognition, this paper analyzes 831 nonconformity reports collected from 30 construction projects in Korea from 2011 to 2014. The correlation analysis revealed that a significant portion of construction defects occurred in the procurement and construction phase and as the pattern of function defect and installation defect. Triggered by human error, defective material and faulty method, these defects are treated by conccession, repair, rework that can significantly lower the cost and schedule performance. This paper is significant in terms of providing a theoretical basis for analyzing correlation among various reasons of construction defects and quantitative measures for establishing effective defect prevention strategies.

Analysis of Road Construction Projects' Escalation under Historical Data-Based Estimate System in Jeju (실적공사비가 적용된 제주도 도로공사의 물가변동률 영향 분석)

  • Hong, Jeong-Ho;Lee, Dong Wook
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.2
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    • pp.667-676
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    • 2014
  • This study has conducted case studies in order to suggest alternatives to the historical data-based estimate system. Price fluctuation calculation methods based on historial cost indexes, standard estimate and construction cost indexes were applied to 9 road construction sites in Jeju for an analysis. As a result, in 5 construction sites (about 56% of 9 sites), the index control rate calculated based upon historical data-based estimate system was higher than that calculated based upon standard estimate and construction cost indexes. Thus the establishment of the requirements for the adjustment of contract price due to price fluctuation delays, which leads to a significant difference in price fluctuation amount. And, in an analysis of construction cost indexes, the indexes for road construction were used for calculating index control rate which ranges from 2.0 to 9.4 percent, indicating the time of construction amount and price fluctuation application has a significant influence on index control rate.

Study on the Risk Factors of Construction Projects since COVID-19 (COVID-19가 건설프로젝트 리스크에 미치는 영향)

  • Lee, Jae-Hyun;Lee, Seong-Hyeon;Lee, Donghoon
    • Journal of the Korea Institute of Construction Safety
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    • v.4 no.1
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    • pp.1-8
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    • 2021
  • COVID-19, which is currently in vogue, is a pandemic with the largest number of deaths since the establishment of the "World Health Organization". It is also expected to have a significant impact on countless construction projects. After COVID-19 hit the construction industry, the risk that they needed to cover, decreased every year. However, the prolonged COVID-19 increased the risks of air delays, material supply, and economic losses. The exact measurements will be needed to be identified and the risks of the current construction projects must have a mitigated risk with a greater proportion. Therefore, the purpose of this study is to analyze and identify the risks that have influenced construction projects to the domestic construction companies due to COVID-19. Based on the risks of the previous construction projects, risk case studies, and risks related to COVID-19, are extracted through surveys, weights. Each risk factor are calculated based on the AHP analysis technique. Thus, it is expected that the results of the risk research on construction projects will change due to COVID-19. It will be presented to cope with the current situation and later pandemic situations.

Analysis on Performance Assessment Framework of Construction Phase for Road Construction Projects (도로건설사업 시공단계 성과평가 프레임워크 연구)

  • Mun, Junbu;Lee, Kangwook;Yun, Sungmin
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.43 no.6
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    • pp.801-809
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    • 2023
  • Road construction projects have a long duration so cost overruns and schedule delays are occurred. However, performance assessment system that can manage and prepare for this in advance is insufficient. In addition, road construction are affected by many factors during under construction. Therefore it is necessary to conduct performance assessment considering the characteristics of roads and prepare for similar projects in the future. The purpose of this study is to provide a framework to evaluate construction phase performance and present a performance management plan using road construction information. Also, This study conducted time adjustment between the start and the finish of the project and developed performance metrics based on absolute and relative indicator. This study analyzed the cost, schedule, and changes of the road project construction process, showing the possibility of advancement of performance assessment and how to use it when planning new road construction projects.