Dynamic planning and control methodology for large-scale concurrent construction projects

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001.Includes bibliographical references (leaves 182-185).Concurrent construction has been widely used for modem construction projects, as a method to shorten time-to-market. Concurrent construction, however, requires a careful and systematic approach to its planning and management, since it also has greater potential to impact the construction process than the traditional more serial method. These industrial trends and challenges in concurrent construction, together with increased understanding of dynamics and complexities of construction, have increased the demand for a more efficient planning and control method. In this context, the simulation-based scheduling method that has the potential to more effectively deal with the dynamic state of construction processes has currently emerged as an alternative to the network-based method. However, despite its potential advantages over the network-based method, very few of the existing simulation tools have overcome their practical limitations and have proven their applicability to real construction processes. As an effort to address some of these challenging issues, this thesis presents Dynamic Planning and Control Methodology (DPM) that has been developed to help prepare a more robust construction plan against uncertainties and to provide policy guidelines for the planning and control of a construction project, taking into consideration the context in which the project is being developed. The use of DPM would be especially beneficial for construction projects performed concurrently and involving higher complexity and uncertainties, ensuring that those projects can be delivered in time without driving up costs.by Moonseo Park.Ph.D

Construction knowledge evaluation using expert index

While the current global economy can be characterized by the intensification of business competitiveness, leaner organizations, the convergence of products and services, and by vast technological developments, the risks and un‐certainties inherent in such a dynamic environment make the management of organizational knowledge even more crucial. Indeed, previous theoretical and empirical‐based studies have proven that knowledge leads to organizational success. Knowledge Management (KM) has particularly gained credence, and continues to generate interest, in academic and business circles. KM is of especial interest to project‐based industries such as construction, as the effective management of knowledge is critical to the survival and continued advancement of a company. In fact, in the construction industry, the implementation of a knowledge management system (KMS) is currently being considered, and an increasing number of companies have already proposed knowledge management initiatives. However, quality of information must take precedence over quantity, especially in the developmental phases of this KMS. Therefore, how to filter and accurately evaluate quantitative and qualitative data becomes a significant challenge. Yet, thus far, only a few studies examining the improvement of knowledge evaluation have been conducted and that researches only focus on the evaluation methods. This research addresses these issues by focusing on knowledge management and evaluation and by specifically addressing how evaluate knowledge effectively. Based on the Active Knowledge Management, this study proposes a process model for effectual construction knowledge evaluation using Expert Index (EI). EI is the level of specialty workers achieve in a certain field after engaging in a knowledge activity. The proposed model will not only enable precise evaluation, but will also provide stimulating knowledge activities; thus, if practically applied, this model could enhance actual organizational success. Santrauka Šiuolaikinei globaliajai ekonomikai būdingas konkurencijos didejimas, organizaciju lankstumas, gaminiu ir paslaugu suartejimas bei didžiuliai technologiniai laimejimai. Ši dinamine verslo aplinka kartu susijusi su rizika ir neapibrežtumais, didinančiais organizacijos žiniu vadybos (ŽV) svarba. Ankstesni teoriniai ir empiriniai tyrimai rodo, kad šios žinios ‐ organizacijos sekmes šaltinis. Žiniu vadyba tampa vis svarbesne akademinei ir verslo aplinkai. ŽV labai domimasi pramones šakose, kuriose didele reikšme turi projektai. Statyba yra viena iš tokiu šaku, joje veiksmingas žiniu valdymas, padedantis užtikrinti imoniu išlikima ir nuolatini vystymasi, yra labai svarbus. Šiuo metu statybos pramoneje diegiamos žiniu vadybos sistemos (ŽVS) ir vis daugiau imoniu pateikia ŽV siūlymu. Būtina siekti, kad žiniu kokybe būtu labiau vertinama nei žiniu kiekis, ypač ŽVS kūrimo tarpsniu. Todel kiekybinis ir kokybinis žiniu atsijojimas tampa rimta užduotimi. Deja, iki šiol atlikta mažai tyrimu, kaip gerinti žiniu vertinima. Atliekant šiuos tyrimus demesys telkiamas tik i žiniu vertinimo metodus. Straipsnyje efektyvus žiniu vertinimas nagrinejamas ŽV metodais. Pasitelkus aktyviaja ŽV kuriamas statybos žiniu vertinimo modelis ir taikomas ekspertu rodiklis (ER). ER išreiškia specialistu, isisavinančiu specifine informacija, žiniu lygi. Siūlomas modelis leis ne tik tiksliai vertinti, bet ir skatinti žiniu gavima. Taigi, taikant ši modeli praktikoje, bus galima gerinti imones veikla. Reikšminiai žodžiai: žiniu vadyba, žiniu vertinimas, ekspertu rodikli

Construction cost estimation using a case-based reasoning hybrid genetic algorithm based on local search method

Estimates of project costs in the early stages of a construction project have a significant impact on the operator\u27s decision-making in essential matters, such as the site\u27s decision or the construction period. However, it is not easy to carry out the initial stage with confidence, because information such as design books and specifications is not available. In previous studies, case-based reasoning (CBR) is used to estimate initial construction costs, and genetic algorithms are used to calculate the weight of the retrieve phase in CBR\u27s process. However, it is difficult to draw a better solution than the current one, because existing genetic algorithms use random numbers. To overcome these limitations, we reflect correlation numbers in the genetic algorithms by using the method of local search. Then, we determine the weights using a hybrid genetic algorithm that combines local search and genetic algorithms. A case-based reasoning model was developed using a hybrid genetic algorithm. Then, the model was verified with construction cost data that were not used for the development of the model. As a result, it was found that the hybrid genetic algorithm and case-based reasoning applied with the local search performed better than the existing solution. The detail mean error value was found to be 3.52%, 6.15%, and 0.33% higher for each case than the previous one

Evaluation methods for construction projects

Financial evaluation methods such as Net Present Value (NPV) and Internal Rate of Return (IRR) are not fully adequate for accounting three practical aspects of construction projects: reinvestment rate, actual amount of required investment, and firm available funds. In a certain type of projects, this inadequacy often results in the inapplicability of NPV, multiple or no IRR problem, systematic bias of IRR, and inconsistent decision signal and ranking between NPV and IRR. Many modified methods have been developed, but hardly succeeded in reflecting construction market reality in an integrated manner. To address this issue, Project Present Value, Project Rate of Return, and Firm Rate of Return are proposed together with an investment decision framework. The proposed methods are designed to be free from all those problems, while incorporating market reality in them. As a result, construction practitioners would have more reliable and economically meaningful decision tools, which lead to the success of their projects. Santrauka Finansiniai įvertinimo metodai, kaip dabartinės vertės (DV) arba vidinės grąžos (VG), neadekvačiai vertina tris praktinius statybos projektų aspektus: reinvestavimo greitį, tikrąjį investicijų ir kapitalo poreikį. Dėl to neadekvatumo tam tikrai projektų rūšiai minėtųjų metodų iš viso neįmanoma pritaikyti. Sukurta daug modifikuotų metodų, tačiau jie sunkiai atspindi statybos rinkos tikrovę integruota forma. Tam pasiūlyta investicinių sprendimų sistema, į kurią integruoti trys metodai: dabartinės projekto vertės, projekto vidinės grąžos ir įmonės apyvartumo. Pasiūlytieji metodai gali įvertinti rinkos realybę. Dabar statybos gamybininkai turės patikimesnes ekonomiškai reikšmingas priemones sprendimams priimti ir galės sėkmingiau įgyvendinti savo projektus. First Published Online: 14 Oct 2010 Reikšminiai žodžiai: finansų valdymas, investicijos, sprendimų priėmimas

Boost, Control, or Both of Korean Housing Market: 831 Countermeasures

Although the Korean government reported a housing supply ratio of more than 100% in the early 2000s, regional and class disparities in the Korean housing sector have not been correspondingly alleviated. Unfortunately, many Korean households are still enduring the economic burden caused by cyclical price variation, while many housing construction companies are on the verge of bankruptcy. To resolve the ever-expanding socioeconomic problems in the housing and real estate sector, the current Korean government proposed 831 Countermeasures, which has since met with much controversy. In an effort to address these issues, this paper utilizes a qualitative system dynamics model to elucidate and interrogate complex Korean housing mechanisms. By mapping bibliographical and experimental knowledge with causal loop diagrams, the positive and adverse effects of the 831 Countermeasures are also analyzed. Finally, based on the research findings, alternative policy guidelines are proposed that can be used to strengthen positive housing structures and obviate negative ones.

Probabilistic Duration Estimation Model for High-Rise Structural Work

The duration of a construction project is a key factor to consider before starting a new project, as it can determine project success or failure. Despite the high level of uncertainty and risk involved in construction, current construction planning relies on traditional deterministic scheduling methods that cannot clearly ascertain the level of uncertainty involved in a project. This, subsequently, can prolong a project`s duration, particularly when that project is high-rise structural work, which is not yet a common project type in Korea. Indeed, among construction processes, structural work is notable, as it is basically performed outdoors. Thus, no matter how precisely a schedule is developed, such projects can easily fail due to unexpected events that are beyond the planner`s control, such as changes in weather conditions. Therefore, in this study, to cope with the uncertainties involved in high-rise building projects, a probabilistic duration estimation model is developed in which both weather conditions and work cycle time for unit work are considered to predict structural work duration. According to the proposed estimation model, weather variables are divided into two types: weather conditions that result in nonworking days and weather conditions that result in work productivity rate (WPR) change. Obtained from actual previous data, the WPR is used with relevant nonworking day weather conditions to modify the actual number of working days per calendar days. Furthermore, on the basis of previous research results, the cycle time of the unit work area is assumed to follow the beta probability distribution function. Thus, the probabilistic duration model is valid for 95% probability. Finally, a case study is conducted that confirms the model can be practically used to estimate more reliable and applicable probabilistic durations of structural work. Indeed, this model can assist schedulers and site workers by alerting them, at the beginning of a project, to project uncertainties that specifically pertain to structural work and the weather. Thus, the proposed model can enable personnel to easily amend, and increase the reliability of, the construction schedule at hand.

A real-time location-based construction labor safety management system

The construction industry continues to record a high number of accidents compared to other industries. Furthermore, the ramifications of construction accidents are growing in terms of both economic loss and loss of life with trends toward larger-scale, more complex projects. For this reason, there is an increasing awareness of the importance of safety management in the construction industry, and the need for more effective safety management techniques. This paper introduces a real-time location-based construction labor safety management system that tracks and visualizes workers’ locations in real-time and sends early warnings to endangered workers. The system is developed by integrating: a real-time locating system (RTLS) for tracking of workers’ location; a location monitoring system for mapping the workers location on a computerized building model; and alarm technology for sending early warnings. The developed system has been applied to an apartment project and an RTLS technology test center in Korea, and proved to be effective in tracking and monitoring workers in real-time and preventing construction accidents. It is envisioned that the developed system will enable proactive construction safety management in South Korea and the methodologies developed in this study will be applicable to other contexts with minimal customization

Military Facility Cost Estimation System Using Case-Based Reasoning in Korea

This manuscript was submitted on January 22, 2010; approved on July 30, 2010; published online on August 3, 2010. Discussion period open until October 1, 2011; separate discussions must be submitted for individual papers.Numerous cost estimations are made repetitively in the initial stages of construction projects in response to ongoing scope changes and often need to be recalculated frequently. In practice, the square foot method, considered an effective method for time-saving, is widely used. However, this method requires a great amount of effort to calculate a unit price and does not consider the uniqueness of each case. Thus, the use of the square foot method could bring about unwanted consequences. For example, in the case of military projects in Korea, significant differences have been reported between estimations made using this method and the actual costs. In an effort to deal with this challenging issue, this research develops a military facility cost estimation (MilFaCE) system, based on case-based reasoning (CBR), using case data from 422 construction projects at 16 military facilities. Based on system validation experiments involving 10 military officers (engineers), the effectiveness of the system in terms of estimation accuracy and user-friendliness is confirmed. Consequently, this research can be a CBR application example of construction cost estimation and a basis for further research into the development of cost estimate systems. DOI: 10.1061/(ASCE)CP.1943-5487.0000082. (C) 2011 American Society of Civil Engineers.This research was supported by grants (R&D06CIT-A03 and 05CIT-01) from the Korea Ministry of Land, Transport, and Marine Affairs and the Ministry of Defense.

Transaction-Cost-Based Selection of Appropriate General Contractor-Subcontractor Relationship Type

Relationships between general contractors and subcontractors are generally formed on a project-by-project basis. However, because of the competitive nature of the construction industry, this traditional arrangement can result in adversarial relationships between general contractors and subcontractors, which can jeopardize potential or ongoing collaborative construction plans. To avoid this problem, close, long-term relationships between general contractors and subcontractors, as in strategic partnerships, must be established. Unfortunately, forming and sustaining such relationships can be time-consuming and cost-intensive. Furthermore, this type of relationship does not necessarily enhance cooperation or work performance. For contractors to successfully establish effective partnerships with their subcontractors, they must select the appropriate relationship by considering the different characteristics of the subcontracted work involved. Based on transaction cost theory, the findings of this study show that transaction costs incurred by general contractors and subcontractors vary according to the type of relationship established. Therefore, for the purpose of comparing transaction costs incurred in both competitive and partnership relationships, transaction-cost-based profit models for both general contractors and subcontractors are developed, respectively, for each relationship type. As well, by applying different strategies to maximize profits in each relationship, and by simulating the parameters affecting the nature of the subcontracted work, the conditions and relationships under which general contractors` profits are optimized have been determined. Finally, based on simulation, practical guidelines for choosing the most appropriate relationship type are proposed.

Championing behaviour of a project manager : determinants and outcomes

The role of individuals in the innovation process is highlighted as system integrator and/or champion in literature, however, little is known about championing role of a project manager. Our contention is that the role of the project manager (PM) is essentially of a champion to enable innovation and achieve desired project performance in construction project environment. Hypothesizing that championing behaviour is determined by a number of individual and situational factors, which in turn effects on level of innovation and project performance, we used correlation and regression analysis to test the hypotheses. A survey was carried out with project managers and project team members in 32 building and civil engineering projects in Singapore to test the hypothesized relationships. The results corroborate the importance of championing behaviour to fostering innovation and achieve better project performance