The present invention relates to a reinforcement assembly for a beam. In at least one embodiment, the reinforcement assembly comprises a carrier member having a front side and a back side, a plurality of mass support sections, and at least one bendable portion disposed between adjacent mass support sections. Each mass support section has an opening extending from the front side to the back side, and a plurality of heat activated expandable masses supported on both the front side and the back side of the carrier member. Each heat activated expandable mass is positioned over a mass support section and each heat activated expandable mass is disposed on the front side being connected through the opening to a corresponding heat activated expandable mass on the back side.