Title:
Full-Scale Testing and Analysis of 20-Year-Old Pretensioned Concrete Box Girders
Author(s):
Yolanda Labia, M. Saiid Saiidi, and Bruce Douglas
Publication:
Structural Journal
Volume:
94
Issue:
5
Appears on pages(s):
471-482
Keywords:
box girders; bridges (structures); concrete (pretensioned); full-scale
test; prestress loss; ultimate test;
DOI:
10.14359/497
Date:
9/1/1997
Abstract:
This research covers the testing of 2 full-scale, precast, pretensioned box girders. The girders were removed from an existing bridge in Reno, Nevada, and had been in service for 20 years. The overall length of the girders was approximately 21.34 m (70 ft). The girders were tested monotonically to failure, while monitoring strain profiles, deflection, crack opening, and strand strain. Several methods were used to test the remaining level of prestress in the girders. Ultimate moments and measured level of prestress were compared to code equations. Measured ductility was compared to ductility behavior as predicted by the code by considering strain profiles, ultimate deflection, and ultimate concrete strain. There was good agreement between code predicted and measured ultimate load. However, both ductility and prestress loss differed significantly from code predictions. Explanations for these differences are proposed in the main body of this paper.