Benjamin P. Thompson

A model specification for FRP composites for civil engineering structures

Abstract A proposed model specification for FRP composite materials for use in civil engineering structural systems is described in this article. The model specification provides a classification systems for FRP materials, describes admissible constituent materials and limits on selected constituent volumes, describes tests for specified mechanical and physical properties, specifies limiting values of selected properties in the as-received condition and in a saturated state, and provides a protocol for predicting long-term property values subjected to accelerated aging based on the Arrhenius model. The model specification is included as an appendix to the article.

Decision-making tools for evaluating the impact of materials selection on the carbon footprint of buildings

The objective of the research described in this article is to improve measurement, prediction and optimization of sustainable building material performance by integrating a decision-making framework for sustainable material selection of building materials with a building information modeling (BIM) tool. Integration of a BIM model with a decision-making tool and sustainable material selection addresses the difficulties of making decisions earlier in the design/build process and allows for specific sustainability trade-off analyses to be conducted, using the actual building conditions and characteristics. It is intended to improve the way building material data is utilized in a building throughout its life cycle, and to model the impact of design, maintenance, operations and occupant behavior modification decisions made in an effort to improve the building’s contribution to a sustainable infrastructure. Pertinent information contained within a BIM model is extracted, and utilized in decision making related to material selection and to the development of ‘what-if’ scenarios. Decision makers will be able to evaluate options for improving their building materials’ environmental sustainability performance. The research provides a new means for sharing data amongst various building modeling programs using a decision analysis model and a new tool for making design decisions related to sustainable building design.

Model Specification for Composites for Civil Engineering Structures

A model specification for fiber-reinforced polymer (FRP) composite materials for use in civil engineering structural systems was developed. The model specification provides a classification system for FRP materials, describes admissible constituent materials, and specifies limits on selected constituent volumes. The specification provides procedures for qualifying FRP composite laminates and for accepting FRP composite parts constructed of qualified laminates. Test methods to obtain mechanical and physical properties were devised, along with stipulation of limiting values for selected properties for both laminates and parts. Based on the Arrhenius model, a protocol was outlined for predicting long-term property values subjected to accelerated aging.

Determining Minimum Contract Time for Highway Projects

An increasing number of state highway agencies (SHAs) are using A (cost) +B (time cost) bidding (A + B bidding) for highway construction. The A + B bidding concept is designed to shorten the total contract time by allowing each contractor to bid the number of days in which the work can be accomplished, in addition to the traditional cost bid. The SHA is then presented with the problem of determining a reasonable range of contract time submitted by the bidders. Most SHAs do not currently restrict the range of B. However, several problems may arise from an unrestricted range of B. First, if no minimum is set for B, a bidder may inflate the cost bid and submit an unreasonably low B, using the excess cost bid to cover the disincentives charged for exceeding the time bid. Second, if no maximum is set for B, then a bidder with a high B and a low-cost bid may be awarded the job and make an unreasonable amount of money from incentive payments. This study develops a quantified model of the price-time bidding contract. A construction cost-versus-time curve is developed from Florida Department of Transportation (DOT) data. The contractor’s price-versus-time curve is then combined with the road-user cost to determine the optimum lower limit to be set on B. Finally, several projects completed by the Florida DOT will be used to illustrate this model.