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Overtime and over-budget construction projects are not pleasant to any stakeholder. Stakeholders want construction projects to be completed without delay and excessive cost. It is possible to meet these objectives by using resource management techniques such as resource leveling. Due to the limitation of resources and different types of them in a construction project, optimizing the resource utilization is crucial. In this paper, a meta-heuristic simulated annealing resource leveling model is presented. The novelty of this model lies not only in the type of modeling and optimization but also in its assumptions. Our model simultaneously allows activities to split and considers a limitation in resource availabilities. The developed model was implemented in a computer program. Then, it was applied to an example from the literature of resource leveling. The model successfully solved the problem. The results of our model are compared with those already available in the literature.Key words: resource management, resource leveling, simulated annealing, meta- heuristic, activity splitting.Les heures supplementaires et les depassements de budget des projets de construction ne sont agreables a aucune partie prenante. Les parties prenantes veulent que les projets de construction soient completes sans retard ni cout excessif. Il est possible d'atteindre ces objectifs, au moyen de techniques de gestion des ressources, comme le nivellement des ressources. En raison de la limitation des ressources et les divers types de ressources dans un projet de construction, optimiser l'utilisation des ressources est primordial. Dans cette etude, on presente un modele metaheuristique du recuit simule pour le nivellement des ressources. La nouveaute de ce modele reside non seulement dans le type de modelisation et d'optimisation, mais aussi au niveau de ses hypotheses. Notre modele permet simultanement aux activites d'etre scindees tout en tenant compte de la limitation de disponibilites des ressources. Le modele developpe a ete mis en reuvre dans un programme informatique. Il a ensuite ete applique a un exemple de nivellement des ressources provenant de la litterature. Le modele a resolu le probleme. Les resultats de notre modele sont compares avec ceux deja disponibles dans la litterature. [Traduit par la Redaction]Mots-cles: gestion des ressources, nivellement des ressources, recuit simule, metaheuristique, fractionnement d'activites., 1. IntroductionA common definition for project is a temporary endeavor undertaken to create a unit product, service or result (PMI 2007). Based upon a more extended definition, a project is [...]

A system of conditional demand equations for wood products in the US construction sector is derived from the relevant end-use cost functions by taking advantage of the duality between the production function and the cost functions. Seven different inputs, including five wood products, labor, and capital, and three different end uses (new housing construction, repair and remodeling, and nonresidential construction) are analyzed. A seemingly unrelated regression estimation procedure is employed using a detailed annual time series database that spans the period from 1950 to 2009. Results suggest large variability in own-price long-term demand elasticity among wood inputs and across end uses. Softwood lumber, for example, is highly inelastic for new housing construction, inelastic for repair and remodeling, and nearly unitary elastic for nonresidential construction. Softwood plywood, on the other hand, is elastic for new housing construction and highly inelastic for nonresidential construction. In addition, we find that dynamic adjustments to long-term conditional intensity factor demand are prevalent across all inputs and among all three end-use categories. Key words: econometric, wood products, construction sector, demand elasticity, dynamic adjustments. Une meilleure comprehension de la demande dans les marches des produits du bois aux Etats-Unis peut clarifier les relations entre les produits et les utilisations finales et contribuer au developpement de modeles du secteur forestier. Un systeme d'equations de demande conditionnelle pour les produits du bois dans le domaine de la construction aux Etats-Unis est derive a partir de fonctions de cout ultime pertinentes en profitant de la dualite entre la fonction de production et les fonctions de cout. Sept intrants differents, incluant cinq produits du bois, le travail et le capital, ainsi que trois utilisations finales differentes (construction residentielle neuve, reparation et renovation, et construction non residentielle) sont analyses. Une procedure d'estimation par regression apparemment independante est employee en utilisant une base de donnees detaillee de series chronologiques annuelles qui couvre la periode allant de 1950 a 2009. Les resultats indiquent qu'il y a une importante variabilite a long terme dans l'elasticite de la demande par rapport au prix parmi les intrants qui sont des produits du bois et selon l'utilisation finale. Le bois d'reuvre resineux par exemple est hautement inelastique pour la construction residentielle neuve, inelastique pour les reparations et les renovations et quasi unitairement elastique pour la construction non residentielle. Le contreplaque de resineux par contre est elastique pour la construction residentielle neuve et hautement inelastique pour la construction non residentielle. De plus, nous observons que des ajustements dynamiques a l'intensite a long terme des facteurs de demande conditionnelle sont frequents parmi tous les intrants et les trois categories d'utilisation finale. [Traduit par la Redaction] Mots-cles: econometrique, produits du bois, secteur de la construction, elasticite de la demande, ajustements dynamiques., Introduction The construction sector is the single largest market for wood products in the US. In 2005, 67% of all wood products (about 7735 million cubic feet) were used in [...]

Identifying spatial-conflict free locations of mobile cranes that could minimize delays associated with crane relocation can result in productivity and safety improvements on construction sites. Existing approaches for identifying possible crane locations are based on two-dimensional (2D) work envelopes created by reasoning about the lift capacities of a crane during operations. Since spatial conflicts related to crane operations typically occur in three dimensions and during any period of operation, representing possible crane locations based on such 2D work envelopes can result in identifying some locations as good when in fact they might result in conflicts and missing possible locations that might be feasible. This paper presents an approach that determines possible locations of mobile cranes based on discrete-event simulation of crane operations incorporating dynamic behaviors of cranes. This approach starts with identifying a search space for possible crane locations by reasoning about a reachability radius of a crane determined by crane characteristics and the weight of the load to be carried. Later, it reduces the search space through boom-line intersection tests. For the remaining locations, it checks for potential spatial conflicts between building components and cranes moving in three dimensions and across time. Validation studies show that the developed approach can accurately identify possible locations for mobile cranes that minimize the relocation of mobile cranes and avoid potential spatial conflicts. DOI: 10.1061/(ASCE)0887-3801(2008)22:1(21) CE Database subject headings: Cranes; Simulation; Conflict; Workspace; Construction sites.

On-site materials-handling operations are error prone and the errors that occur significantly decrease construction productivity. New technologies and sensing devices can enhance materials-handling management practices on construction job sites. This paper describes a study that aimed to determine the potential benefits of the deployment of global positioning system (GPS) technology within the materials-locating processes on industrial projects. Its main goals were (1) to evaluate the technical feasibility and (2) to quantify the direct benefits in terms of process duration derived from the integration of GPS devices within pipe-locating processes. A field trial was conducted and its results indicated significant time savings. This study also analyzed additional potential benefits derived from the use of GPS in this scenario. CE Database subject headings: Construction management; Construction materials; Data collection; Global positioning; Resource management.

The paper argues that an effective solution to information and knowledge management (KM) needs of practitioners in the construction industry can be found in the provision of an adapted knowledge environment that makes use of user profiling and document summarization techniques based on information retrieval sciences. The conceptualization of the domain through ontology takes a pivotal role in the proposed knowledge environment and provides a semantic referential to ensure relevance, accuracy, and completeness of information. A set of KM services articulated around the selected ontology have been developed, using the Web services model, tested, and validated in real organizational settings. This provided the basis for formulating recommendations and key success factors for any KM project development. CE Database subject headings: Knowledge-based systems; Information retrieval; Construction industry.

The systems that historically have been used to collect data for time studies of construction operations are manual in nature and limited to the observer's field of view. Global Positioning System (GPS) technology incorporated into an onboard instrumentation system can be used to autonomously collect position and velocity data without the field of view limitation. Data must be collected at a short time interval to provide the level of detail necessary for operations analysis. Thus the issue becomes managing the data and identifying the relatively key records that mark the start and stop of activities. A field observer identifies the key times in real time with instantaneous decisions of when one activity stops and the next starts based on enormous volumes of visual information. This work developed a methodology for making equivalent decisions based on GPS data and presents the procedures developed to identify the key records necessary to calculate activity durations. A case study is used to illustrate application of the system to an earthmoving operation. Also, it is postulated how the information can be used in discrete event simulation. DOI: 10.1061/(ASCE)0733-9364(2005)131:8(920) CE Database subject headings: Geographic information systems; Construction industry; Data analysis: Information management; Time studies.

Ergonomics is a key issue in the construction industry. Many work tasks and associated equipment and tools are not designed with ergonomics principles in mind. Often, in the development of power tools for construction, any attention to ergonomics is restricted to the human-machine interface and handle design. The need for ergonomics intervention in the development process originates from considerations of safety, health, physical work load, and productivity. It is argued that in each of these respects, the construction industry has lower standards than other industries and therefore has a need and opportunity for improvement. A multi-level ergonomics approach is proposed addressing these issues. The approach defines five levels of ergonomics intervention, from designing individual tools for safety, to designing wider aspects of construction and work flow for optimal productivity. This holistic approach is illustrated using case study examples of the development of power tools and work methods. Keywords: Product development; Product ergonomics; Ergonomics approach

This paper presents a unique treatment of competitive bidding theory as applied to pricing engineering services. Unlike low-bid procurement, the selection of engineers and design consultants is often based on several factors such as quality, availability, reputation, resume, and references, and these criteria may or may not include price. From preliminary interviews, the authors conclude that there is a need for a systematic method of evaluating potential job opportunities and determining fair market prices. This hybrid model, Value-Bidding, refocuses the competitive bidding model from a fee-based selection criteria to a value-based selection criteria. Value-Bidding utilizes an established marketing research methodology, conjoint analysis, to establish the probability of winning based on multiple factors. The resulting analytical model enables engineers to analyze market conditions, evaluate client priorities, systematically track competitors, and optimize proposals, while maximizing the probability of winning, maximizing profit, and optimizing price. DOI: 10.1061/(ASCE)0733-9364(2005)131:6(621) CE Database subject headings: Bids; Pricing; Market research; Professional role; Consulting services; Engineering services; Business administration; Construction industry.

The role of institutional arbitration has become significantly less commercially viable in the international construction industry as a primary means of dispute resolution because of the uniqueness of the construction process. As a result, the construction industry has developed an innovative form of primary dispute adjudication called the Dispute Adjudication Board (DAB). This paper will show the need for an efficient dispute resolution process because of the globalization of the construction industry. It will focus on the standard contract forms of the Federation Internationale des Ingenieures-Conseils (International Federation of Consulting Engineers) (FIDIC), which are widely used in international construction projects. The paper will then discuss recent developments in the FIDIC, including the development of the DAB to address the fundamental need for a commercially viable means of construction dispute adjudication. CE Database subject headings: Construction industry; Dispute resolution; Contracts; International factors.

When investing in information technology (IT) applications, construction managers implicitly account for the value of adding future applications to the original investment as the business and technical environment changes. A real option model links uncertainty to the value of an underlying traded asset, providing an objective measure of this managerial flexibility. A case study that investigated the value of options to extend a general contractor's software platform showed that it is possible to construct a real option model which measures the value of this flexibility, since the major risk (the architect's adoption rate) is external to the investing organization. In another case study, a contractor evaluated the value of the pilot project in view of the information it is expected to generate. Since the risks are internal, a decision analysis model is used instead of a binary option model. The results show that it is possible to quantify the value of managerial flexibility for IT investments in the architecture, engineering, and construction industry, but that the proper method to use is contingent on the nature of the investment project. CE Database subject headings: Decision theory; Investments; Information technology (IT); Construction industry; Financial management.

Continual development in construction techniques results in emergence of specialized formwork systems. A new system will have to compete with in-use systems for adoption in a target operation. Thus, it is essential that decision makers anticipate the acceptability of new systems before making decisions to acquire them. Estimating acceptability basically assesses how features of a new system are comparable to that of in-use systems. Therefore, analogy is a focal factor for the acceptability estimating process. Neural networks (NNs) are more suitable to model construction problems requiring analogy-based solutions. A NN-based approach was employed to anticipate the acceptability of new formwork systems. The study collected data from a group of 40 users in Egypt. A set of six performance characteristics that mostly pertain to acceptability estimating were identified. The study used the analytical hierarchy process to produce pairs of a performance characteristics' vector and the corresponding acceptability value, and utilized the developed pairs to train NNs. Finally, tests on trained NNs using unseen data indicated satisfactory performance. CE Database subject headings: Neural networks; Decision making; Artificial intelligence: Data collection: Construction management; Egypt.

Real-time control of on-site construction is a growing field still in its infancy. Labor inputs is an important project performance indicator to be controlled because it is a leading input in construction projects. A model for automated control was developed and verified in the field, to demonstrate that labor inputs can be automatically measured and controlled. The concept behind this development is that indirect data--workers' locations measured automatically at regular time intervals--can be collected automatically and converted into labor inputs using computerized algorithms. The model was implemented in a concept-proving prototype, which was applied in three construction projects to verify the concept and test the feasibility of developing a full-scale prototype. The encouraging results of the field experiments showed that it is possible to convert worker's locations automatically measured at regular time intervals into labor inputs, and thus automatically control them. The expected accuracy of such a system is [+ or -] 10-20%. Additional work is currently underway to develop a location measurement system and other components of the full-scale prototype. DOI: 10.1061/(ASCE)0733-9364(2003)129:4(437) CE Database subject headings: Automation; Bench marks; Data collection; Labor; Project management; Performance evaluation.

As the complexity and size of the projects undertaken by horizontal directional drilling (HDD) contractors rapidly increase, there is a growing need for the development of dedicated software designed to meet the industry's special needs and requirements. This paper presents the results of a survey of the HDD industry's software needs as well as a summary of commercially available software specifically designed for this industry. In addition, the development of two computerized applications tailored for the HDD industry are described. The first of these applications is an integrated data management system that combines asset management, cost control, estimating, and project tracking capabilities, enabling decision makers to closely monitor field performance in terms of expenditure and productivity. The second application is a simulation model developed for optimizing the utilization of drilling rigs and hydro-vacuum trucks on large-scale urban projects. Both applications are designed to improve the planning, estimating, and productivity of directional drilling projects, ultimately reducing the cost of expanding underground infrastructure networks. DOI: 10.1061/(ASCE)0733-9364(2003) 129:4(446) CE Database subject headings: Drilling; Computer software; Cost control; Project management; Construction industry.

This paper tests the assertion that experienced contractors are more competitive than inexperienced contractors by measuring the effect of experience on bidding competitiveness for building contracts procured by a regular client. Contractors are grouped into experienced and inexperienced contractors, and two levels of contractors' experience are identified: (1) bidding experience only and (2) bidding plus construction experience. Results of two-sample t tests show that experienced contractors are more competitive than inexperienced contractors. Contractors' competitiveness in respect of school contracts and other contracts are further compared in evaluating the relationship between the project type and experience effect. Experienced contractors are, on average, more competitive in competing for school contracts. It emerges that the factor of project type familiarity amplifies the experience effect. A comparison of experienced contractors' competitiveness in bidding for (1) new building works and (2) alteration and extension works shows that the effect of experience would be more significant when contract works packages are highly standardized. DOI: 10.1061/(ASCE)0733-9364(2003)129:4(388) CE Database subject headings: Competition; Bidding; Contractors; Construction industry.

This paper presents a predictive tool that uses safety factors to estimate accident risk for processes commonly employed on construction sites. The tool is demonstrated in the context of the utility-trenching process. Based on expert surveys, preplanning, supervision, and training are identified as critical safety factors needed to predict accident risk when evaluating safety performance related to trenching operations. Preplanning has a greater impact on excavation tasks than supervision and training, while conversely, supervision and training are more important during the pipe installation phase of trenching operations. DOI: 10.1061/(ASCE)0733-9364(2003)129:4(431) CE Database subject headings: Accident prediction; Safety factors; Construction site accidents; Trenching.

Negotiation is an important aspect of the construction process. Different negotiation theories and models are available and have been deployed in a variety of situations. In some cases, these have been incorporated into multiagent systems that address a number of engineering problems. This paper is concerned with the approach adopted in the development of a multiagent system for construction claims negotiation (MASCOT). It reviews the key negotiation theories, outlines the peculiarities of the domain (construction claims negotiation), and discusses the choice of an appropriate negotiation mechanism for MASCOT. Of particular interest is the integration of Zeuthen's bargaining model with a Bayesian learning mechanism, which addresses the characteristics of construction claims negotiation. An example is presented to demonstrate the application of the MASCOT model in a real construction claim case. DOI: 10.1061/(ASCE)0887-3801(2003)17:3(180) CE Database subject headings: Artificial intelligence; Claims; Negotiations; Construction industry.

Despite a decrease in industry level measures in construction productivity, there has been a steady increase in construction productivity at the activity level. This research examines equipment technology as one factor that may explain that increase. The relationship between changes in equipment technology and partial factor productivity is examined for 200 activities over a 22 year time period. Specifically, the paper examines the relative impact of different types of equipment technology for five technology factors: energy, control, functional range, information processing, and ergonomics. Through ANOVA and regression analyses, it is found that activities that experienced a significant change in equipment technology also witnessed substantially greater long-term improvements in partial factor productivity than those that did not experience a change. CE Database keywords: Construction industry; United States; Productivity; Construction equipment.

The change in productivity is studied for six different pieces of earthmoving equipment over a period of 15 years. It is shown that the production rate of this group of equipment has increased 1.58% on average per year. During the same period, without adjusting for inflation and making specific assumptions, the unit price of production has increased at an average rate of 1.77% per year. The results of this analysis may be used in modeling obsolescence costs in equipment replacement analysis. The equipment considered includes two models of wheel-type loaders, one track-type loader, one scraper, and two track-type dozer models. CE Database keywords: Construction equipment; Productivity; Costs; Case reports.

The development of construction equipment has followed the major changes in global transportation. In 1420, Giovanni Fontana was dreaming of and diagramming dredging machines. Development of the steam shovel was driven by a demand for an economical mass excavation machine to support the era of railroad construction. The Cummins diesel engine was developed in the early 1900s as the road-building phase of transportation construction began. In the short term, the basic machine frame will not change, but productivity, accuracy, and utility should improve because of enhancements. Machines will evolve into a mobile counterweight driven by an energy-efficient powerplant. This mobile counterweight will serve as a work platform for an array of hydraulic tools, and it will have synthesized computers that instantly communicate by satellite with distant management teams reporting diagnostics, production, and position. CE Database keywords: Construction equipment; Excavation; High technology.

The reliability of the techniques adopted for damage assessment is important for bridge management systems. It is widely recognized that the use of expert systems for bridge damage assessment is a promising direction toward bridge management systems. However, several important issues need to be addressed, such as the management of uncertainty and imprecision, the efficiency of fuzzy rule based reasoning, and the need of an explanation facility to increase confidence about the assessment results. To address the issues arising from using expert systems, this paper is aimed at developing an expert system for assessing bridges based on an expert system shell, which is called the fuzzy Petri net based expert system (FPNES). Major features of FPNES include the ability to reason using uncertain and imprecise information, knowledge representation through the use of hierarchical fuzzy Petri nets, a reasoning mechanism based on fuzzy Petri nets, and an explanation of the reasoning process through the use of hierarchical fuzzy Petri nets. Therefore, this expert system for assessing bridges does not impose any restriction on the inference mechanism. Furthermore, this approach offers more informative results than other systems. An application to the damage assessment of the Da-Shi bridge in Taiwan is used as an illustrative example of FPNES.

Computer integrated construction (CIC) has recently evolved to maximize the integrated utilization of information systems throughout the project's entire life cycle and across different business functions. CIC is a broad and strategic concept, not a specific system. Complicating CIC solutions are the dynamics of business requirements and technology development, It is difficult, therefore, to design systems that are based on the available technology, resources, needs, and benefits. This situation calls for an effective CIC planning methodology, particularly on a company level. This paper proposes a planning methodology that incorporates comprehensive issues for real-world CIC implementation. Measures and factors influencing information systems assessment are investigated. To represent the complex measurements in a simplified manner, a CIC portfolio is also developed. Managerial issues are stressed throughout the planning process to help make CIC more viable and efficient. A case study using this methodology is presented.

The problem of accurate estimation of earthmoving productivity has intrigued many researchers for many years, but there is yet no model that will predict the output of such operations with a satisfactory degree of confidence for all situations. The problem is exacerbated by the occurrence of hauler bunching that results in many deterministic models overestimating productivity. Systems analysis methods can be used, such as queuing theory or simulation, but they are generally impractical to the average site planning engineer. This paper investigates the results obtained from over 140 separate earthmoving operations taken from four different highway construction projects. Initially, the effects of bunching are determined, and many factors that influence productivity are identified. To investigate the relationships between earthmoving operating conditions and both productivity and bunching, and to develop a deterministic model that will enable earthmoving operations to be planned for many different situations with relative ease, stepwise multiple regression techniques are used. The results indicate that there is a strong linear relationship between operating conditions and productivity.

Techniques for measuring distances, relative heights, and angles have improved significantly during the last decades. Some of these techniques can be used in the Architecture, Engineering, and Construction industry to improve the precision of measurements being made currently using traditional equipment. Other techniques can be used to record information that could not be obtained practically using the traditional equipment. Cost comparisons are made for different scenarios to show that the substantial initial cost of the new hardware can be compensated for by lower labor cost and shorter duration. This paper also points out some of the salient features of the new metrology options. For example, locating the three-dimensional coordinates of a point is necessary for robotic control. In this case, new equipment must be used if the traditional equipment cannot obtain the coordinates at a rate that is useful to control the movement of the robot.