Daisuke OGIYAMA

Design of Girder at Intermediate Supports in Continuous Composite 2-I-Girder Bridges

Masatugu NAGAI

In order to reduce the construction cost and to attain higher durability, the construction of
continuous composite 2-I-girder bridge has been increasing and, in recent years, two guidelines
for designing them have been published. However, there exists a difference in two guidelines.
One is the way to evaluate the hogging bending moment of the girder at intermediate supports
and the other is the definition of the stress in reinforcing bars for evaluating crack widths.
In this paper, using a 3D finite element analysis, the hogging moment and stress of reinforcing
bars in cracked slab are investigated. The followings are results obtained from this study.
1) The hogging bending moment at intermediate supports has to be evaluated based on the
beam theory. The moment obtained from the beam theory should not be reduced based on
Specifications for Concrete Highway Bridges in Japan.
2) Though the stress in reinforcing bars in cracked slab from FE analysis shows a little bit
smaller values compared to the average stress, it is recommended to use the average value.