The aim of this study is to improve the potential of bridge countermeasures by concentrating on material performance and use. The study will identify countermeasure material needs for specific members and attack modes. It will rate the performance of available materials to meet these needs in three basic countermeasure functions. It will also develop a research plan to improve their performance, or, where possible, to develop new material combinations. Specifically, the project will aim at the questions: (1) What are the best uses of a particular material or material combination -- direct resistance; sacrificial damping; alternate load paths? (2) What is the potential for improvements to the material or material combination to better perform any one of these three basic tasks? (3) How does the performance of these materials or material combinations rate on specific bridge components identified in field evaluation studies, and against the higher attack loads identified in these field evaluations?
- DEFINE THE PROBLEM: A rating of current materials' performance or potential performance in each of these four countermeasure types (discussed in (2a)). A rating and report on the predicted effects of candidate material improvements in performing each of these four functions on vulnerable bridge members. This rating will include an assessment of the effects on the seismic response of the bridge, as well as accidental (low-angle) collision.
- OUTLINE THE SOLUTION: The central objective of this study is to analyze the problem, outline the functions of materials in addressing that problem, and develop initial, working drafts of the following:
- Material specifications for countermeasures for each critical bridge component.
- Inspection and maintenance methods. Development of these specifications will require the development of these support functions.
- Test protocols to rate material performance and capabilities in each of the three countermeasure types: (1) direct resistance, (2) load damping, and (3) alternate load paths.
- Define the required research tasks:
- Development plans to countermeasures using selected material improvements, identified in objective 2, to meet the material requirements of each countermeasure function identified in objective 1. The development plans will include recommendations, for appropriate members, to assure multihazard support either noninterference, or improvements where feasible, in the seismic response of the bridge, or accidental collision resistance.