Prestressed plastic foam structural member
AssigneeWesley Staples
InventorsJack Richards, Marilyn Richards
Life of this patent
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Abstract
A lightweight structural member made of prestressed plastic foam is provided, the prestress provided by a plurality of tendons disposed within the foam to which tensile forces are applied during mold casting of the structural member, the tendons being retained in tension by bonding between the tendons and the foam, or by way of anchors which are spaced along the tendons to retain the tendons in immobile condition, one or more skin layers also being optionally provided. A method for producing a lightweight structural member of prestressed plastic foam is also provided.
Claims19
A prestressed structural member comprising:
- a polymer foam element having an exterior surface;
- and
- at least one tendon disposed within said polymer foam element at a predetermined location, said tendon extending substantially entirely through said foam element from a first predetermined external surface of said foam element to a second predetermined external surface, means for retaining said tendon in tension and in substantially immobile condition within said foam element, wherein said tendon possesses residual stresses thereby inducing a prestress in said structural member, said retaining means comprising a plurality of anchors fastened to and protruding from an exterior surface of said tendon, said plurality of anchors being disposed on a portion of said tendon within said polymer foam element.
A prestressed structural member comprising:
- a polymer foam element having an exterior surface;
- a first and a second group of tendons, said first group of tendons being spaced apart and being disposed to extend across a width of said structural member, said second group of tendons being spaced apart and being disposed to extend across a length of said structural member, said tendons being made of strands of a porous material;
- means for retaining said tendons in tension and in a substantially immobile condition within said foam element, wherein said tendons possess residual stresses thereby inducing a prestress in said structural member;
- wherein said retaining means comprises a self-adhesion bond between said tendons and said plastic foam;
- and
- at least a first skin layer, said first skin layer covering substantially a first exterior face of said structural member.
A prestressed structural member comprising:
- a polymer foam element having an exterior surface;
- at least one tendon disposed within said polymer foam element at a predetermined location, said tendon extending substantially entirely through said foam element from a first predetermined external surface to a second predetermined external surface, means for retaining said tendon in tension and in a substantially immobile condition within said foam element, wherein said tendon possesses residual stresses thereby inducing a prestress in said structural member;
- and
- wherein said tendon is made of a porous material, and said retaining means comprises a self-adhesion bond between said tendon and said polymer foam element.
Dependencies are inferred from the claim text.