Fire Behavior of Post-Installed Anchoring Systems скачать в хорошем качестве

Fire Behavior of Post-Installed Anchoring Systems

Presented By: Nicolas Pinoteau, CSTB Description: Post-installed anchors and post-installed reinforcement are often used in construction to provide flexibility, to correct mistakes on jobsites, and to enable extensions and strengthening of structural elements. Unprotected anchors of all types directly exposed to fire conditions may experience failure due to softening of the steel (e.g., stripping of threads). In addition, fire conditions may reduce the strength of the concrete and thus the breakout strength associated with anchorages. Most significantly, organic binders (e.g., epoxies) account for a significant percentage of adhesive anchoring products used for threaded rod and reinforcing bar connections. These products have a heightened sensitivity to elevated temperatures, including in fire conditions where the internal concrete temperatures can approach or exceed their glass transition temperature. Testing and design methodologies for post-installed reinforcement follow the “Resistance Integration Method” established in Europe in, e.g., European Assessment Document 330087 based on work by Pinoteau and others. Work is ongoing to implement this approach into ACI testing and design standards for anchors in concrete. Additional steel and concrete failure mode considerations are needed for post-installed mechanical and adhesive anchors, which are also intended to be addressed in ACI testing and design standard update. This paper provides basic information about anchoring systems, their sensitivity to elevated temperatures, and the assessment and design methodologies anticipated in ACI documents. Design examples using the Resistance Integration Method are provided.