Achieving Worldwide Code Acceptance for the Use of Advanced Composite Materials to Strengthen Civil Structures

Abstract

In the 1990s, the use of advanced composite materials for infrastructure initiated with the California Department of Transportation (Caltrans), as an alternative to steel jacketing bridge columns for seismic retrofit. Caltrans turned to an independent material testing facility, Aerospace Corporation, to assist in the development of the first prequalification test program for advanced composite materials in civil infrastructure, which focused on durability requirements of composite materials under various environmental conditions. After the Northridge earthquake in 1994, the International Code Council Evaluation Service (ICC-ES), formerly International Conference of Building Officials (ICBO) developed an acceptance criteria (AC125) for the use of advanced composite materials to strengthen non-ductile reinforced concrete and masonry structures. The AC125 criteria was substantially influenced by structural testing at the University of California, San Diego and has been adopted by numerous countries, including New Zealand and Canada, as a preferred criterion to evaluate various composite systems. The American Concrete Institute (ACI) has also been influential in the development of guidelines for civil structures, with the first guideline published in 2002 and since adopted and referenced internationally. Other industries (e.g. water and waste water transmission) have developed their own unique requirements for durability testing and inspection. In the UK, the Concrete Society developed guidelines (TR55 & TR57) for the design, acceptance, inspection, and monitoring of composite materials, while Germany developed a general building approval program (Zulassung by DIBt), similar to ICC but requires more rigorous durability testing. These requirements have evolved over the years and will continue to change along with the associated codes and guidelines. This paper will review the various durability and materials testing requirements that have been developed, with a brief overview of the guidelines and codes being developed to allow these advanced composite materials to become more accepted for use in civil structures.