International Concrete Abstracts Portal

Title: Flexural Analysis of Prestressed Concrete Structures

Author(s): M. B. CAVALCANTI, B. HOROWITZ

Publication: IBRACON

Volume: 1

Issue: 4

Appears on pages(s): 331-364

Keywords: Prestress, Continuous, Secondary Effects.

Date: 12/30/2008

Abstract:
In the computation of the strength capacity of prestressed concrete structures prestressing may be viewed as strength or load. “Model 1” considers prestressing strands as integral part of the cross section where prestressing operation induces imposed deformations corresponding to prestraining. Alternatively,“Model 2” considers prestressing as external loading, composed of a self-equilibrating system of forces on the anchorages and transversely on concrete. After transfer prestressing strands are considered as conventional reinforcement in computations except that the deformation axis is displaced to take into account pre-elongation. In spite of Model 1 being the most commonly used in designing of continuous beams and officially adopted by NBR 6118 it has the inconvenience of the mandatory consideration of additional secondary effects known as hyperstatic moments which must be taken into account in ultimate strength analysis. The computation of secondary effects is simple for continuous beams but becomes more involved in