Journal of Construction Engineering and Management

Construction work is often a risky undertaking for all parties involved, and risk management is essential in dealing with potential exposures. One of the possible options in any risk management approach is the shifting of designated potential risks to financially strong institutions, which, for an agreed premium amount, are willing to assume the financial responsibility for any loss incurred. This paper presents a case study and a methodology for determining the expected loss to an insurance company when insuring for liquidated damages. It is directed to engineers and construction managers faced with providing a surety or owner with a quantification of the risk associated with a project completion date.

Scheduling with constrained resources, particularly skilled labor, is a major challenge for almost all construction projects. In the literature, various techniques have been developed to reduce consequent project delay of constrained resources. Most of these techniques assume single-skilled resources and use heuristic rules to decide which activity will receive the resource first and which ones to delay. To improve existing solutions, this paper introduces some modifications to heuristic resource-scheduling solutions, considering multiskilled resources. The proposed approach stores and utilizes information about the resource(s) that can be substituted when there is a shortage in another one. Using this information, less utilized resources can be combined to substitute the shortages in constrained resources during the shortage period, taking into consideration the loss in work productivity. To automate the proposed algorithm, a macroprogram has been written on a commercial scheduling software. An example application is presented to show the improved results of the proposed approach over existing heuristics. The use of the proposed approach as a better resource management tool within the construction industry is then discussed.

Computerized intelligent systems can simulate human expertise as well as analyze and process vast amounts of data instantaneously. This paper presents a hybrid intelligent computerized model for constructed facilities surface quality assessment. The model uses computers to analyze digital images of the areas to be assessed to identify and measure defects. Moreover, neural networks are used to train the system to automate the process and replicate the experts' knowledge in identifying the defects. Most techniques, currently used in construction quality assessment, rely mostly on subjective criteria. The model applies digital image processing and neural network techniques for constructed facilities surface quality assessment to make the process objective, quantitative, consistent, and reliable. Highway steel bridge coating assessment was used to exemplify the generic model.

This paper classifies diving modes available for civil construction: (1) scuba; (2) surface-supplied air with no decompression; (3) surface-supplied air with decompression; (4) surface-supplied gas; and (5) saturation. It then discusses the characteristics of each mode, moving from the most limited, scuba, to the most unlimited, saturation. It also provides some details of diving work services.

Most companies lack a formal method to address maintainability during the project delivery process, yet maintenance can seriously affect project costs. To address the opportunities available to companies through the effective inclusion of maintainability concepts, the Construction Industry Institute formed the Maintainability Research Team. Using a combination of recent literature, a questionnaire survey, personal interviews, and case studies with industry professionals, the research team organized maintainability best practices into a model implementation process. Developed from the owner's perspective, the model process has two levels: corporate and project. Milestones, steps, and activities further define each level. The benefit of the model process is that it provides owners with a starting point for implementing maintainability. This paper outlines the proposed model process and describes the potential roles and benefits of maintainability on various types of projects.

The cost of constructing and tooling a semiconductor facility, which is currently more than $1 billion, is expected to double by the year 2000, driving semiconductor chip manufacturers to adopt strategies to minimize cost to maximize the return on investment. What seems to be an inevitable transition to the larger, 300-mm wafer will have a widespread impact with massive economic implications. Preliminary tool designs and process approach standards suggest increased automation of material handling and storage systems, increases in utility consumption, tool height and weight requirements, and schedule compression. Moreover, the contamination sensitivity of the 300-mm wafer might require modification in the fab construction protocol, which in turn could affect labor productivity. Such changes will have a significant impact on construction methods, materials, and management techniques. This paper discusses the key areas in which research is necessary, focusing mainly on issues that have the maximum impact on design and construction of 300-mm fabs. While not providing solutions, this paper is intended to act as a catalyst for further research as 300-mm technology moves closer to becoming a reality.

Construction activities are often influenced by factors such as weather, labor, and site conditions. When several activities are influenced by the same factor, their durations may be correlated. If many activities along a path are correlated, the variability of path duration will increase, possibly increasing the uncertainty of completing the project by a target date. This paper presents the simulation-based model NETCOR (NETworks under CORrelated uncertainty) to evaluate schedule networks when activity durations are correlated. Based on qualitative estimates of the sensitivity of each activity to each factor, uncertainty in an activity's duration distribution (grandparent) is distributed to several factor subdistributions (parents). Each subdistribution is broken down further into a family of distributions (children), with each child corresponding to a factor condition. Correlation is captured by sampling from the same-condition child distributions for a given iteration of the simulation. NETCOR integrates the effect due to each factor at the path level. Awareness of the factors to which a path is sensitive can provide management with a better sense of what to control on each path, particularly on large projects.

Current approaches to network scheduling do not consider the correlation between activity durations. When activity durations are correlated, the variability of path and project durations may be increased. High variability in a project's duration increases the uncertainty of completing the project by a target date. The model NETCOR (NETworks under CORrelated uncertainty) has been developed to evaluate schedule networks when activity durations are correlated. The NETCOR model builds upon a factor-based procedure to indirectly elicit correlation. An activity duration model disaggregates the effect of uncertainty by factors from a duration distribution (grandparent) for each activity. Correlation is captured by a child-distribution approach that further breaks down the factor-subdistribution (parent) based on the factor conditions. This paper demonstrates the practical application of NETCOR to a current construction project. Using the same inputs, the program evaluation and review technique and several simulation analyses that do not consider correlation also are evaluated. Comparison of the results shows the significance of considering correlation in scheduling analysis.

This paper discusses an evolutionary approach for simplifying the process of building and experimenting with computer simulation models of heavy earthmoving construction operations. Simulation models are automatically generated from high-level descriptions in CAD by making use of add-on tools to capture key information. This includes product information (facility to be constructed or components thereof), construction resources utilized, construction methods or processes followed, and general project data. The automation and generalization of this approach relied heavily on advancements in the area of computer simulation, specifically in the use of modular and hierarchical simulation concepts. This paper discusses the required CAD developments, the modular simulation modeling approach, and a prototype earthmoving simulation system.