Transcript AASHTOWare Bridge Rating – Curved Girder Module

AASHTOWare Bridge Rating –
Curved Girder Module
Vanessa Storlie, E.I.T.
Chad Clancy, P.E.
Presentation Organization
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Background Info
Modeling
Analysis
Results
Conclusions
Background Info
• Performed Beta Testing of Curved Girder
Module in BrR 6.5
– Needed to use a bridge where design force
effects and resistances were available
– Bridge had to be curved but with a small enough
radius where the curvature would have an effect
– Selected a four-span continuous unit with a
radius of 1145.92 feet; four girders in crosssection spaced at 10’-4”; bridge was designed by
MM
Modeling – General Information
• Appurtenances (medians, parapets,
railings, etc.) do not have to be input as
“generic” as shown in example.
• Define different diaphragm/cross-frame
types using “Diaphragm Definitions”
Modeling – Superstructure Definition –
Definition Tab
Modeling – Superstructure Definition –
Analysis Tab
Modeling – Structure Framing Plan
Details
Modeling – Structure Framing Plan Diaphragms
Modeling – Structure Framing Plan
Schematic
Modeling – Diaphragm Loading Selection
• Check the boxes for
which you want force
effects to be
calculated
• Adds a significant
amount of time to the
analysis.
Modeling – Member Alternatives
• Curved girders input the same way as
straight girders.
• Girder web does not have to be defined
with separate sections for each different
cross-section
• For bearings aligned along a chord line,
angles should be closer to zero than to 90.
• Local z-axis is transverse and y-axis is
vertical
Modeling – Visual Verification of Input
• Traditional framing plan, cross-section, and
girder schematics are still available.
• 3D schematics showing elements are available
when using 3D FEA analysis
Analysis – Analysis Settings
Results
• Dead load and live load moments and
shears can be obtained from “View
Analysis Report”; element level
forces/stresses can be found in xml files
by using “View analysis output”
• Report tools function but it appears as
though there are small bugs in populating
the reports for both LFR and LRFR.
Results
• Compared BrR moments and shears to BSDI values used for
design. Generally very similar for interior girders, some differences
for exterior girders that with additional effort could be eliminated.
Conclusions
• BrR provides moments and shears similar
to those from BSDI analysis used for
design.
• Some significant differences in positive
moments – reason yet to be identified
• Need to look at cross frames
• More comparisons planned as part of
rating 5-span units on the Huey P. Long
bridge in New Orleans