Patent ID: 7421825
Filing Date: 2008-09-09
Classification: E04B,E04C

Abstract:
1. Doubly prestressed roof-ceiling construction for extremely large spans, said construction comprising a flat soffit grid of greater than 50 meters in length, a prestressed upper girder formed of two transversely extending pieces, the two pieces being interconnected by a wedge forced between the two pieces to prestress the upper girder, and interconnecting pipe-rods extending between the soffit grid and the upper girder, the soffit grid including longitudinally interconnected square shaped hollow tubes forming grid elements and cables extending centrally through the square shaped hollow tubes with the cables extending along an entire length of the square shaped hollow tubes, conductor plates located in and extending across a width of said square shaped hollow tubes for prestressing the soffit grid, the cables extending through the conductor plates located in the square shaped hollow tubes, the square shaped hollow tubes being filled with one of hard expanding foam and lightweight concrete for corrosion protection and thermo-insulation of the soffit grid.