Filled composite structure with pre-stressed tendons

A filled structure comprising:

• a fiber reinforced resinous hollow structure having a tensile strength of at least 30,000 psi, and an inside surface forming a boundary which defines a space,
• a hard core within said space, the hard core having a density of at least 35 pounds per cubic foot and a compressive strength of at least 1500 psi, the hard core being formed from a mixture of particulate cementitious material and liquid, said hard core being of material such that shrinkage thereof is negligible upon hardening, and
• at least one tendon under stress and disposed in said hard core, said tendon being constructed and arranged to exert stress on said hard core.

A filled structure comprising:

• a fiber reinforced resinous hollow structure having a tensile strength of at least 30,000 psi, and an inside surface forming a boundary which defines a space,
• a hard core within said space, the hard core having a density of at least 35 pounds per cubic foot and a compressive strength of at least 1500 psi, the hard core being formed from a mixture of particulate cementitious material and liquid, said mixture being such that it expands its volume as it hardens, expansion of the mixture being restrained by the hollow structure and the hard core exerts a force against the inside surface of the hollow structure, and
• at least one tendon under stress and disposed in said hard core, said tendon being constructed and arranged to exert stress on said hard core.