الفهرس 
LITERATURE REVIEWOnly 14 pages are availabe for public view
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Abstract
he aim of the current research is to consider the effects of
continuity, skew and diaphragm on the live load distribution characteristics
of skew steel bridges. Current specifications including the AASHTO
Standard Specifications 1996 and AASHTO LRFD 1998 Specifications do
not account for reduction in moments due to the effects of transverse cross
bracing and continuity resulting in conservative bridge design. The
objective is fulfilled by conducting an extensive parametric study on
several bridge models to evaluate the effect of the parameters.
A theoretical two - equal span bridge model was constructed using
the finite element method. The deck slab was modeled as isotropic fournodded
shell elements with six degrees of freedom at each node. The steel
girders were modeled as three dimensional beam elements with six degrees
of freedom per node and were connected to the shell elements through rigid
links. The analysis was performed using the finite element commercial
program SAP2000.
An AASHTO Standard truck was selected and positioned in such
locations to maximize both positive and negative moments. These positions
were determined by developing influence area diagrams .ased on the results of the parametric study, the live load
distribution factors were computed and compared to those of AASHTO
1996 Standard Specifications and LRFD Specifications.
Additionally, an innovative technique based on correlating the
deflected shape of cross bridge sections with intermediate diaphragms
equivalent deck slab thickness was used to find the effect of cross
diaphragms.
Further, the stiffness of typical bridge was estimated using a twodimensional
analysis. Allowing determining live load distribution factors
using two - dimensional bridge models.