Abstract

Time-and-cost control is an essential management function for successful delivery of engineering, procurement, and construction projects. Considerable research efforts have been expended on this topic. However, those methods often suffer from a lack of integrated tracking and control. In general, control systems generate variance reports and provide analysis, diagnosis, and forecasts of project cost and duration at completion. Nevertheless, there is a need not only for an efficient computational environment that allows data sharing among project team members in the control process, but also for providing reasons behind unacceptable performance and for improving forecasting capabilities. This research presents a web-based system that supports project time-and-cost control in an integrated manner. The developed system utilizes object-oriented modeling to represent project deliverables. A set of control-objects is designed to represent the work tasks in the construction process. A hierarchy structure using a three-level performance evaluation method not only identifies the time-and-cost variances at each control level, but also evaluates the calculated variances against a pre-defined criterion. Eighteen key indicators chosen from the literature serve as sensors to highlight problematic areas associated with unfavorable performance. Four causal models are developed to define the relationships among the indicators. Fuzzy binary relation and union operations are employed to explain the reason(s) behind unfavorable performance and to suggest related corrective action(s). An indicator-based fuzzy forecasting model is developed to assist in predicting time and cost at completion and at interim future horizons. A prototype system "IT/CC" (Integrated time and cost control) is developed in the structure of Three-Tier Client Server architecture to implement the developed methodology. Sixty web forms serving different input, browsing, and editing purposes are developed. Five databases, namely, Project, Factor, Reason, Case , and Historical are developed to facilitate the implementation of the IT/CC system. The IT/CC system takes advantage of the World Wide Web to provide an efficient data sharing and collaborating environment for tracking and control of construction activities. It also provides timely generation and dissemination of site progress reports. Daily, weekly, monthly and/or yearly, period-by-period, and to-date project performance reports are generated to provide the status at project, control-object, and resource levels. The on-line data sharing ability provides real-time data for team members and allows them to react in a timely manner.