Prestressing as action or resistance
There are two distinct approaches to the design checks of prestressed concrete members - the prestressing can be either treated as resistance (integral part of the section) or as action (load)
Prestressing as resistance
- Considers the prestressing strands as integral part of the cross section, where prestressing operation introduces imposed deformation corresponding the pre-elongation of the active reinforcement.
- Hyperstatic effects must be considered.
Prestressing as action
- Considers prestressing as external loading consisting of a self-equilibrating system of forces in the anchorages and the transversally in the concrete. After transfer prestressing strands are considered as conventional reinforcement, only taking into consideration the pre-elongation.
Treatment in different codes
AASHTO LRFD 2007
- Based on C5.7.1, prestressing is treated as part of resistance
Eurocode 2 (1992)
- Based on article 5.10.1, bullet 2, the effects of prestressing can be considered as an action or a resistance
- M. B. Cavalcanti, B. Horowitz: Flexural Analysis of Prestressed Concrete Structures, IBRACON Structures and materials journal, Volume 1, Number 4 (December, 2008) p. 331 - 364, ISSN 1983-4195 - describes two methods that can be used to evaluate capacity of prestressed concrete members; method 1 treats prestressing as integral part of the section, while method 2 treats prestressing as external load.
|Home > Topics > Prestressed Concrete|
|Overview||Overview · Hyperstatic forces|
|Prestress losses||Friction losses · Anchorage set losses|
|Miscellaneous||Tendon · Post-Tensioning · Partial prestressing · Restraint moment · Prestressing as action or resistance · Standard prestressed girders · Magnel diagram|
|Related Topics||Reinforced Concrete|