Indirectly prestressed, concrete, roof-ceiling construction with flat soffit.

摘要

An indirectly prestressed concrete roof-ceiling construction is a prefabricated element for constructing large-span industrial buildings. The construction includes a distinctly wide and thin concrete soffit plate and an upper concrete girder of an inverse "V"-shaped cross section, interconnected by slender steel pipe-rods that are used to stabilize the upper girder against lateral buckling and to prevent the plate and the girder from getting closer or further away from each other. Prestressing of the soffit plate causes compression in the upper girder which passively (indirectly) pushes the ends of the construction, acting on some eccentricity over the center of gravity of the cross section, causing rotation of its ends, bending in that way the soffit plate upwards. There are two efficient methods of prestressing these constructions.