Title:
Enhancing Strength and Ductility of Post-Tensioned Segmental Box Girder Bridges
Author(s):
Azez HindiI, RobertT Macgregor, Michael E. Kreger, and John E. Breen
Publication:
Structural Journal
Volume:
92
Issue:
1
Appears on pages(s):
73-94
Keywords:
box beams; bridges (structures); ductility; girders; post-tensioning; prestressed concrete; prestressing steels; segmental construction; strength; Structural Research
DOI:
10.14359/1472
Date:
1/1/1995
Abstract:
This paper reports tests of a three-span reduced-scale segmental box girder bridge model post-tensioned with external tendons. The objectives of this phase of the study were to determine the effect of using external tendons discretely bonded at the intermediate diaphragms and/or using grouted internal tendons on the strength and ductility of external tendon bridges, and to experimentally determine and analytically predict the external tendon maximum stress and flexural capacity of the bridge. The experimental studies were done in three phases. In the first phase, the model was constructed using the span-by-span method and post-tensioned with external tendons discretely bonded at only two or four intermediate diaphragms in each span. At the end of the first phase, ultimate flexural tests were conducted to establish the ductility and strength of the model. In the second phase, a complete evaluation and repair was carried out to determine the condition of the previously tested model and restore it to a good condition before the beginning of further testing. During the secondphase, the external tendons were discretely bonded at all 10 intermediate diaphragms in each span. Ultimate flexural tests were then conducted to examine the effect of this discrete bonding. In the third phase, ultimate flexural tests were conducted to examine the effect of supplementary ungrouted or grouted internal tendons on the strength and ductility. The test results indicated that discrete bonding of external tendons and/or using grouted internal tendons substantially improved strength and ductility of this kind of construction.