Doubly prestressed roof-ceiling construction with grid flat-soffit for extremely large spans

摘要

A doubly prestressed roof-ceiling construction with grid flat soffit for extremely large-span is a prefabricated element intended for assembling roofs of extremely large-span buildings with a flat soffit. The construction includes a grid soffit construction and an upper concrete girder of a modified "T" shape or of an inverse "V"-shaped cross section, interconnected by slender steel pipe-rods that stabilize the upper girder against lateral buckling. The empty openings within elements of the horizontal grid are fulfilled with plates wherewith a flat soffit is achieved. The construction is prestressed by the double prestressing. The grid-soffit is prestressed centrically and the upper girder is prestressed by a wedge at the midspan.