Abstract: An expandable structural member comprises two outer skin members, a plastically deformable reinforcing layer arranged between the two outer skin members, and a foamable polymer composition coated on at least one of each adjacent surface of the reinforcing layer and the respective outer skin member. Each adjacent surface of the reinforcing layer and the respective outer skin member contact one another and are intermittently bonded to one another, with the intermittent bonds on one surface of the reinforcing layer being non-aligned with the intermittent bonds on the other surface of the reinforcing layer. Additionally, the foamable polymer composition is foamable by application of heat to the structural member, whereby the foamed polymer resulting from application of heat to the structural member expands the outer skin members from contact with the reinforcing layer at non-bonded areas and plastically deforms the reinforcing layer into a three-dimensional reinforcing configuration.