Journal of Construction Engineering and Management

Project cost is most sensitive to its schedule. The construction project environment comprising dynamic, uncertain, but predictable, variables such as weather, space congestion, workmen absenteeism, etc., is changing continuously, affecting activity durations. The reliability of project duration forecast can be enhanced by an explicit analysis to determine the variation in activity durations caused by the dynamic variables. A computer model is used to simulate the expected occurrence of the uncertainty variables. From the information that is collected normally for a progress update of the tactical plan and by simulating the project environment, the combined impact of the uncertainty variables is predicted for each progress period. By incorporating the combined impact in the duration estimates of each activity, the new activity duration distribution is generated. From these activity duration distributions, the probability of achieving the original project completion time and of completing the project at any other time is computed.

A method for selecting the most desirable construction strategy is proposed in this paper. A decision analysis framework is developed considering the information on relative risk, along with the information on cost, benefit, and consequences of each construction strategy. Many factors affect the safety of construction operations. Labor skill, supervisors' experience and attendance, condition of falsework, weather conditions, type of equipment, level of operator's experience, etc., may be considered as the main factors that affect the safety of construction operations. From an engineering point of view, these factors are always desirable to be in their best states. However, it may not be practical in many cases due to time and money constraints. Consequently, the risk of failure and cost of construction operations, and the consequences of failure need to be estimated in order to decide about the optimum construction strategy. The decision problem is complicated since the state of the factors are generally expressed in linguistic terms. The theory of fuzzy sets is used to translate these terms into mathematical measures and to estimate the risk of failure. The proposed method is illustrated with the help of an example.

Aggregate blending models that incorporate the optimization of two objectives with their priority levels are presented. The two objectives include the minimization of the mean deviation (or mean absolute deviation) from the midpoint of specification limits and the minimization of the unit cost of the blend. The models are applicable to any number of aggregates and can be used to provide the optimum proportions corresponding to a given priority level or to establish trade‐off curves between mean deviation and cost. The stochastic elements of aggregate gradations are formulated and incorporated into the models. Both the deterministic and stochastic models are applied to a numerical aggregate blending problem, and extensions of the models to accommodate some practical cases are presented.

The Fair and Reasonable Markup (FaRM) is the smallest markup that satisfies the Required Rate of Return (RRR) of the contractor for the particular (or at least the general risk‐class of) project at hand. The model is based on reasonable and easily‐accessible information, and will result in a Minimum Acceptable Price (MAP). The firm cannot accept the project at a price below this MAP without diminishing the “equityholders' wealth.” A modified version of the FaRM Pricing Model for certain contracts under which home‐office overhead expenses must be recovered through FaRM is also presented. Once the FaRM Pricing Model has been implemented, contractors can make more intelligent pricing decisions. Instead of using a subjective markup, which may ignore the cash‐flow differences of various jobs, contractors using FaRM Pricing Model can bid lower on projects which are more attractive and become more competitive while satisfying their RRR. This should result in lower costs to owners. Conversely, by bidding higher on the less‐attractive jobs, contractors will still maintain their RRR should they obtain the contract.

The American Concrete Institute's methodology for designing formwork adequate for its loading is condensed, organized, and simplified into a two‐page, step‐by‐step format of equations and instructions that cover most formwork design situations. Plotted design curves are shown and their limitations discussed.

An analysis of the construction resource utilization tradeoffs, which occur from constructability improvements, provides insight into the constructability improvement process. Matrices of construction and engineering impacts likely to result from constructability improvements are presented. Constructability improvements collected on a large industrial construction project are analyzed for their impact to the job. Frequencies of occurrence of both desirable and undesirable impacts are noted, as are the cost‐significances of the various impact types. Constructability strategies and methods for achieving the most cost‐beneficial impacts are presented. Numerous findings are presented, such as the following: (1) The likelihood of delays may be decreased most effectively by increasing engineering information availability and understandability; (2) the amount of required construction manpower may be most effectively decreased by simplifying the design, combining design elements, and seeking optimal design‐originated construction techniques such as optimal construction systems, modularization, and improved design details. Of course, additional engineering effort may be required; and (3) construction activity durations may also be most effectively decreased by seeking optimal design‐originated construction techniques.

In a building process that enables a proper flow of product information among the “Users of Information” (Agents), a “Product Information System” is proposed. The system established in connection with a set of criteria involves five subsystems (Thesaurus, Summarized Data, Manufacturers, Compatibility Tables, and Detailed Data) linked with each other. Agents looking for product information can enter the system through the subsystems Thesaurus or Manufacturers, and they can decide on the choice of appropriate products at the first stage (Summarized Data), whereby they can find access to the subsystem Detailed Data afterwards for the detailed information needed. The complete code presents a medium for a common language among the users of product information.

This paper is mainly concerned with evaluating the validity of the Craftsman Questionnaire for determining lost manhour estimates. The validity of the Craftsman Questionnaire has been questioned since it was introduced in the construction industry. To examine its validity, the background of the Craftsman Questionnaire is reviewed. Secondly, an analysis of the data collected from past studies is conducted. Herein, sources of inaccurate estimates are revealed. Thirdly, a research method called criteria validity is employed to investigate the validity of the Craftsman Questionnaire by comparing its measures with those of Work Sampling. Although the comparison of results do not reach an absolute conclusion at this stage, the experiment still gives evidence of the validity of employing Craftsman Questionnaires to determine lost time estimates.