Structural member with equalized internal tension

A structural member comprising:

• an elongated, four-sided, box-like fiberglass body shell having two opposite ends;
• a pair of metal end caps engaging said ends;
• four loop-shaped filament wound bands extending longitudinally through said body shell, each of said bands having two parallel, endless side edges, said body shell having four flat interior surfaces each in contact with one of said side edges;
• anchor means for securing said bands to said caps, said anchor means including a pull member at one end of said body shell having a threaded opening therein and a distribution member defining a socket forming part of the surface of a sphere in which said pull member is received, said pull member defining part of the surface of a smaller sphere and thereby being pivotably movable in said socket, and said distribution member having lugs thereon engaged by said bands;
• and
• tensioning means for adjustably positioning said pull member comprising a threaded shank engaged by said threaded opening in said pull member, a head attached to said shank, a plurality of serrations on said head, and drive means attached to said head for rotating said tensioning means and for breaking away from said head when a predetermined tension has been applied.