AC321 - Fiber-Reinforced Polymer Systems

Fiber-reinforced polymer (FRP) systems in construction use strong fibers (such as carbon or glass fibers) embedded in a polymer resin to strengthen structural elements. These systems are often used to retrofit or reinforce existing buildings – for instance, by wrapping fiberglass or carbon fiber sheets around a concrete column or beam and saturating them with epoxy, the member's load capacity and ductility can be greatly increased once the resin hardens.

FRP materials are lightweight and non-corroding, yet have very high tensile strength thanks to the fibers. They provide a way to add reinforcement without heavy steel or bulky additions. Acceptance criteria make sure that FRP retrofit systems provide reliable strength improvement and that the materials (fibers and resins) perform well together under real-world conditions. For structural wood applications, see composite wood products (AC265) standards.

This acceptance criteria provides a basis for evaluating fiber-reinforced polymer retrofit systems that may not be directly covered by existing codes. It establishes testing protocols, structural enhancement requirements, and quality standards needed for code approval of these advanced reinforcement systems.

• Nationwide acceptance by building officials for FRP retrofit systems
• Streamlined approval process for carbon and glass fiber reinforcement
• Third-party verification of structural enhancement performance
• Enhanced marketability for structural retrofitting applications

• ICC Evaluation Service