Title:
Rational Approach for Predicting Stress in Beams with Unbonded Tendons
Author(s):
Ozgur Ozkul, Hani Nassif, Padit Tanchan, and Mohamed Harajli
Publication:
Structural Journal
Volume:
105
Issue:
3
Appears on pages(s):
338-347
Keywords:
deflection; finite element; high-strength concrete; nonlinear analysis; prestressed concrete; unbonded tendon
DOI:
10.14359/19793
Date:
5/1/2008
Abstract:
This paper presents a rational approach for the analysis of concrete beams prestressed with unbonded tendons. The proposed methodology considers the beam and tendon as a trussed beam system that allows for the rational use of equilibrium and compatibility equations as well as the law of conservation of energy to predict the overall behavior at various load levels. The methodology was validated using results from tests performed on a total of 25 high-strength concrete (HSC) beams as well as test data available in the literature. Various parameters, such as area of reinforcing steel, concrete strength, area of prestressing steel, effective prestress, and span-depth ratio, were considered. Results from the experimental study include deflection and strain in prestressing strands, reinforcing steel, and concrete. Based on the analytical study, an equation for predicting the stress at ultimate was derived. In comparison with experimental results, both the analysis model and the equation predicted stresses accurately.