Prestressing system for wood structures and elements

Abstract

The present invention is a prestressing system for wood elements and structures and a method from prestressing wood beams. In its most basic form, the system for prestressing structures comprises a plurality of members arranged in a predetermined configuration, at least one non-metallic prestressing tendon, having a material stiffness less than that of steel, disposed in such a manner as to fasten together the members, and stressing means attached to at least one end of the prestressing tendon to exert a tensile force on the tendon and an equal and opposite compressive force drawing the members together. In the preferred embodiment, the tendons are manufactured from fiber reinforced plastic and the members are arranged in side by side relation to form a deck. The deck includes a series of aligned holes through the members, through which the prestressing tendons pass and are secured and prestressed. In alternate embodiment of the invention, prestressing tendons are used to secure and prestress stress laminated T sections and box sections and to secure timber trusses. The present invention is also directed to a system and method for prestressing beams. In its most basic form, the system comprises at least one nonmetallic tendon, at least one opening disposed longitudinally through a lower portion of the element, a pair of anchors disposed at the ends of each prestressing tendons, and a pair of bearing plates disposed between the anchors and the bearing surface of the beam. In operation, the tendons are disposed within the opening, the bearing plates are disposed against the bearing surfaces and the anchors are tightened such that a tensile force is exterted on the tendons and such that said bearing plates exert a substantially equal an opposite compressive force on the element beam. In an alternate embodiment, the opening is filled along the tendon with a resin and the anchors are removed after the resin has cured.