Prestressed Concrete Roof Structures

It is substantially prestressed during production in a manner that strengthens it against tensile forces which will exist when in service.

Prestressed concrete roof structures.

Prestressed concrete is a form of concrete used in construction. Prototype i that had a clear span of 6 1 m 20 3 ft and a depth of 0 6 m 2 ft for a span to depth ratio of 10 and prototype ii that had a clear span of 18 4 m 60 8 ft and a depth of 2 6 m 8 5 ft for a span to depth. Double tees may be used for many types of buildings. The primary prestressed concrete beams of the floor roof or like structure are first of all erected in position parallel one to another and spaced at predetermined distances apart and spanning the breadth of the structure and after this has been done elements are assembled between and in the same plane as the primary beams which extend at right angles to the primary beams and which co act.

Prestressed membrane roofs have been designed since the invention of prestressed concrete. Prestressed concrete is a combination of high strength concrete and steel strands. Precast prestressed concrete trusses were introduced in 1978 in the aci journal article titled prestressed concrete trusses. 3 5 this compression is produced by the tensioning of high strength tendons located within or adjacent to the concrete and is done to improve the performance of the concrete in service.

They are described in the basic books written by pioneers of prestressed concrete. This combination makes a very strong structural material that is used in the building of roof slabs bridge girders and railroad ties. Double tees are the most widely used prestressed concrete product in the minimum span range. Prestressed concrete was invented and patented in 1886 by henry jackson a san.