Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Flexurally Rigid Support of Prestressed Hollow Core Slabs with Post-tensioned Beams
Abstract Flat slabs with long spans can be economically manufactured only in the form of precast prestressed concrete elements. However, the precast slab elements must be supported on a beam within the column strip. The beam resists the loads from the precast hollowcore concrete slabs and transmits these to the columns. Prestressed hollowcore slabs are reinforced exclusively with prestressing strands. The cross-sections of these prestressed hollowcore slabs have hollow cores that are separated from each other by narrow unreinforced webs. The compressive stresses due to prestressing enable the webs to provide the required shear resistance, even without reinforcement. However, the cross-sections and hence the webs react very sensitively to shear deformations as well as to transverse bending and transverse stress. This loading arises in particular from the forces imposed by the precast slabs on a flexural beam. Deformation of the flexural beam cannot be prevented without an active force supporting the flexural beam. A new structural concept takes these requirements into account. A flush beam for supporting the precast prestressed concrete slabs, including the prestressing cable with parabolic geometry is manufactured. Manufacture of the column strip takes place with a thin partly precast slab as integral formwork. The prefabricated board is manufactured in the prestressing bed and is already fitted with the longitudinal and stirrup reinforcement for the column strip. The spacers for the vertical position of the prestressing cables to be subsequently installed are already provided in the plant as well. The installation of the prestressing cables along the column strip in accordance with the predetermined geometry gives rise to deflection forces that counteract the external actions. Counteracted by this active force, the deformations are controlled to such an extent that no deformation occurs under predetermined actions. The deflection forces due to prestressing are able to ensure flexurally rigid support of the prestressed hollowcore slabs. The danger of reduced loadbearing capacity of the hollowcore slabs no longer exists.
Flexurally Rigid Support of Prestressed Hollow Core Slabs with Post-tensioned Beams
Abstract Flat slabs with long spans can be economically manufactured only in the form of precast prestressed concrete elements. However, the precast slab elements must be supported on a beam within the column strip. The beam resists the loads from the precast hollowcore concrete slabs and transmits these to the columns. Prestressed hollowcore slabs are reinforced exclusively with prestressing strands. The cross-sections of these prestressed hollowcore slabs have hollow cores that are separated from each other by narrow unreinforced webs. The compressive stresses due to prestressing enable the webs to provide the required shear resistance, even without reinforcement. However, the cross-sections and hence the webs react very sensitively to shear deformations as well as to transverse bending and transverse stress. This loading arises in particular from the forces imposed by the precast slabs on a flexural beam. Deformation of the flexural beam cannot be prevented without an active force supporting the flexural beam. A new structural concept takes these requirements into account. A flush beam for supporting the precast prestressed concrete slabs, including the prestressing cable with parabolic geometry is manufactured. Manufacture of the column strip takes place with a thin partly precast slab as integral formwork. The prefabricated board is manufactured in the prestressing bed and is already fitted with the longitudinal and stirrup reinforcement for the column strip. The spacers for the vertical position of the prestressing cables to be subsequently installed are already provided in the plant as well. The installation of the prestressing cables along the column strip in accordance with the predetermined geometry gives rise to deflection forces that counteract the external actions. Counteracted by this active force, the deformations are controlled to such an extent that no deformation occurs under predetermined actions. The deflection forces due to prestressing are able to ensure flexurally rigid support of the prestressed hollowcore slabs. The danger of reduced loadbearing capacity of the hollowcore slabs no longer exists.
Flexurally Rigid Support of Prestressed Hollow Core Slabs with Post-tensioned Beams
Friedrich, Thomas (Autor:in) / Klein-Holte, Ronald (Autor:in)
06.08.2017
10 pages
Aufsatz/Kapitel (Buch)
Elektronische Ressource
Englisch
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