Abstract: A support plate and reinforcement member may be mounted within a hollow side sill between a rocker and crossmembers for a vehicle framework. The support plate may include flanges along either edge and a straight, projecting face between the flanges. The reinforcement member, mounted on the support plate proximate to an outer surface of the side sill, may include flanges along either edge and a wavy projecting face between the flanges. Contact portions of the projecting face for the reinforcement member may contact an interior of the side sill at regions aligned with where the side sill mounts to the crossmembers, with intervening portions of the projecting face, in areas adjacent energy absorbing crush cans, extending less far from the flanges. The intervening portions may also be laterally offset from the contact portions, to provide larger weld areas.