Self-supporting prestressed metal girder - includes two symmetrical cables above and below connected by vert. tie rods

摘要

The girder and cables may be made of high strength steel and the girder is of metal sheeting which is elastically deformed into an upward-curving concave shape. The metal sheets are inserted in pairs into a wire-stretcher and are pre-stressed into a shape maintained by triangular tie-rods placed on. The girder may contain two bottom cables of different shape, and the additional cables improve the girder load bearing capacity and reduce deformation.