Title:
Design of Partially Prestressed Post-Tensioned Beams with Unbonded Tendons
Author(s):
Perumalsamy N. Balaguru
Publication:
Concrete International
Volume:
3
Issue:
11
Appears on pages(s):
30-41
Keywords:
concrete construction; costs; partial prestressing; post-tensioning; prestressing steels; serviceability; strength; structural design
DOI:
Date:
11/1/1981
Abstract:
A design procedure to proportion partially prestressed post-tensioned beams with unbonded tendons is presented. Both strength and serviceability are considered. The procedure is based on the philosophy of load balancing method of design proposed by T. Y. Lin. The cross-sectional dimensions and the amount of nonprestressed steel are determined by designing the beam as a reinforced concrete cross section to resist 70 percent of the external live load moment. This particular fraction of load was arrived at using a parametric study. The area of prestressed steel is calculated to satisfy the strength requirements under full live and dead load. Under service load condition, the section is analyzed as a reinforced concrete cross section subjected to lateral loads and an eccentric force representing the prestressing force. A detailed numerical example is solved, step by step, to show the applicability of the proposed method.