Today’s engineering applications suffer from a severe integration problem. Engineering, i.e. the entire process, consists of a myriad of individual, often complex tasks. Most computer tools support particular tasks in engineering, but the output of one tool is different from the others’. Thus, the user must re-enter the relevant information in the format required by each tool. To achieve a collaborative engineering environment, engineers need some means for relating the information produced by existing software tools. In this paper, a new framework to handle the time-cost trade-off problem in project network is presented. The framework integrates the capabilities of two commercial software, Microsoft Excel™ (spreadsheet), and Microsoft Project™ (project management), with a state-of-the-art knowledge-base called InnerCircle2000™, to solve the mentioned problem interactively.