Title:
Selection and Design of Partially Prestressed Concrete Sections for Strength and Serviceability
Author(s):
A. S. Prasada Rao
Publication:
Structural Journal
Volume:
88
Issue:
3
Appears on pages(s):
330-339
Keywords:
partial prestressing; prestressed concrete; serviceability; strength; stresses; structural design; Design
DOI:
10.14359/3124
Date:
5/1/1991
Abstract:
Describes an iterative algorithm for cracked partially prestressed concrete members under symmetric bending, including the gradual effects of shrinkage, creep, and relaxation. The algorithm envisages optimum utilization of the section, either at the service-load stage, with appropriate built-in checks that insure the required collapse strength, or vice-versa. This method covers pretensioned and post-tensioned members with cross-sectional shapes not necessarily of unsymmetrical I. The prestressed and nonprestressed reinforcements can have individual mechanical properties. The method leads to designs that consume substantially less concrete than the designs obtained using the other methods discussed in the paper. This algorithm guarantees that the stress at prestress transfer stage does not exceed the permissible values. The prior knowledge of self-weight moment is not necessary in this method. This method insures that the stresses in the prestressed and nonprestressed reinforcement, as well as in the concrete, will generally be very close to the permissible values. The algorithm basically involves a two-step iterative process and is programmable.