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This paper examines the characteristics of discrete-event simulation systems in terms of their application breadth (general or special purpose), modeling paradigm (process interaction versus activity scanning), and flexibility (programmable or not). Several construction simulation systems are examined with primary emphasis on CYCLONE and STROBOSCOPE as representatives of the wide range of tools that are currently available. CYCLONE is a well-established, widely used, and simple system that is easy to learn and effective for modeling many simple construction operations. STROBOSCOPE is a programmable and extensible simulation system designed for modeling complex construction operations in detail and for the development of special-purpose simulation tools. The characteristics of these systems, as well as other recent developments, illustrate that an effective general-purpose simulation tool for construction is in essence one based on extended forms of activity cycle diagrams and the activity scanning modeling paradigm. As explained through several examples, these representations are indeed the most convenient and intuitive for construction simulation systems. Furthermore, the programmability of such a system is the principal factor that determines its power, flexibility, and ease of learning and use.

The major drawback of the low bid method, often used for competitive bidding in the U.S. construction industry, is the possibility of awarding a construction contract to a contractor that submits either accidentally or deliberately an unrealistically low bid price. Often, such an occurrence works to the owner's and contractor's detriment by promoting disputes, increased costs, and schedule delays. To address this problem, other countries have adopted the average bid method and award the contract to the contractor whose price is closest to the average of all bids submitted. This paper presents a competitive bidding model for the average bid method and explores its merits relative to the low bid method. The bidding process is analyzed both mathematically and through Monte Carlo simulation. The final results of the average bid model, as well as Friedman's low bid model, are presented in four nomographs that can be used to analyze a competitive situation without the need for any mathematical or numerical manipulation. A comparison of the two methods reveals that the average bid method and its variations have the potential to improve contracting practices both for the owner and the contractor and deserve the industry's increased attention.