Straight and curved steel I-girder bridges - Computational Analysis and Design of Bridge Structures - page 229

Concrete deck
(shell element)

z
y

x

Bearings

Foundation springs

Steel girders
(frame element)
Figure 7.36 Modeling detail of the 3D finite element model in the abutment area.

7.6 2d and 3d IlluStrated exaMPle of a gloBal
and loCal ModelIng of a SIMPle-SPan
Steel I-gIrder BrIdge—I - 270 MIddleBrook
road BrIdge, gerMantown, Maryland

MD Bridge No. 1504200 I-270 over Middlebrook Road is a simple-
span composite steel I-girder bridge with a span length of 42.7 m (140′).
Located at I-270 over Middlebrook Road near Germantown, Maryland,
it carries three traffic lanes in the southbound roadway and five traffic
lanes in the northbound roadway. This bridge has a 76° parallel skew
of its bearing lines. The bridge diaphragms are inverted K-type braces
with top and bottom chords. All of them are parallel to the bearing lines.
A research project sponsored by the U.S. Department of Transportation's
Research and Innovative Technology Administration (RITA), under
the Commercial Remote Sensing and Spatial Information (CRS&SI)
Technologies Program required a pilot testing bridge to develop and per-
form a LT field monitoring test of a wireless Integrated Structural Health
Monitoring (ISHM) system. The Middlebrook Road Bridge with active
fatigue cracks at the connection plates of the K-type bracing was selected.
Complete pilot testing was performed using acoustic emission (AE), accel-
erometer, deflection, and strain sensors for bridge information collection.
To simulate the bridge behavior under traffic load, global and local mod-
els were built, of which the global model was used to monitor the global