Sticky Situation: A Case Study on FRP and HRA Interaction

Externally applied fiber reinforced polymer (FRP) fabrics are a common product for strengthening concrete structures. External reinforcing systems must consider the existing structure’s strength without the external reinforcing, as well as the performance of the external reinforcing system during a fire. FRP systems lose their strength at temperatures lower than the activation temperature for common fireproofing systems, and they are generally sensitive to high temperatures. This presentation reviews the “weird” FRP strengthening project for a building near the east coast of the US in a non-seismic zone where the high temperature case was not fire and of a relatively known and short duration. On this project, the system being strengthened was specified to have hot-fluid applied waterproofing between the structural slab and the topping slab. Hot-fluid applied waterproofing is applied at temperatures that exceed the typical service temperature range for FRP systems. As a result, the project involved significant coordination between architects, engineers, and manufacturers to come up with a solution that satisfied all parties.