TOWARDS SIMPLIFIED COMPUTER-BASED ANALYSIS OF SKEWED-BRIDGES
TOWARDS SIMPLIFIED COMPUTER-BASED ANALYSIS OF SKEWED-BRIDGES
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Date
1987-09
Authors
ABUBAKAR, ALIYU AZIZ
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Abstract
ABSTRACT
Needs for aesthetics, protection of abutments, and safety
requirements of greater speeds on highways, demand better
alignment. In order to achieve these, skew bridges are
frequently built. The analysis of such structures poses
specific difficulties to bridge designers, for example,
response to torsional motions when the skew angle is greater
than 20°.
In this study the structural behavior of skew bridge
decks of various configurations and loading conditions is
presented. Element models of the structure are discussed
through the matrix displacement method. In addition,
discretisation of the deck through its representation as a
plane grillage of discrete interconnected elements is fully
discussed. Loadings to BS5400 and load cases and combinations
at both ultimate and serviceability limit states are provided.
Special attention is given to the formulation of the problem in
a systematic manner, which makes it suitable for computerized
analysis of any bridge deck that is represented as an
assemblage of discrete interconnected elements.
Further, an attempt has been made to provide a simplified
approach to the use of these tools, so that their fruits may be
made available to the designer without the need to perform
complicated analysis in the design office. Having preselected
a structure, the engineer can then identify a particular chart
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and read directly the value of the structural response
concerned without performing any rigorous analysis. Clearly, a
great economy of time and effort is achieved, if for many
structures such as highway skew bridges that might not be
analysed conventionally, much detailed analysis can be replaced
by the use of suitable charts.
Finally, a FORTRAN 77 computer program, GRID, is
presented for the transverse analysis of bridge decks. It
allows reinforcement to be proportioned for transverse as well
as stirrups to be proportioned for longitudinal shear and
torsion. Documentation, sample input and output, and a source
listing as well as analysis aid charts are provided. It is
hoped that bridge designers would find it convenient to use
these charts.
Description
A thesis submitted to the
Postgraduate School, Ahmadu Bello
University, in partial fulfillment of
the requirements for the degree of
M.Sc. Structural Engineering.
Department of Civil Engineering,
Ahmadu Bello University, Zaria.
Keywords
SIMPLIFIED, COMPUTER-BASED, ANALYSIS, SKEWED-BRIDGES