Concrete Bridge Case Study
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Waterway Bridge
Bridge Integrates Durability with Aesthetics
The Gulf Intracoastal Waterway Bridge in Matagorda, Texas, replaces
a floating swing bridge as the only bridge leading to Texas’
Matagorda Peninsula. The swing bridge was a retrofitted floating
barge and was becoming uneconomical to operate and maintain. The
new bridge provides 73 feet of vertical clearance and a wide 320-foot
main span and shipping channel.
The bridge integrates durability and aesthetics. It was constructed
with cast-in-place high performance concrete segments with a 28-day
concrete compressive strength of 6 ksi. Class F fly ash was incorporated
to improve durability in the concrete footings, columns, segmental
superstructures, and approach pretensioned beams and deck slab.
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The traditional shape of the segmental box beam was altered by
the designer to help the superstructure visually flow into the substructure.
The segmental boxes have their traditional flat-bottom shape at
midspan. The bottoms of the segments then gradually change to a
V-hull shape as the segments approach the piers (columns).
 The
approach spans are 141 ft. and 145 ft. long and consist of multiple
AASHTO Type VI precast, pretensioned concrete girders with a concrete
deck. To transition from a multi-girder superstructure to a segmental
superstructure presented an aesthetic challenge to the designer.
The solution was placing ear walls on top of the bent cap to block
the view of the ends of the pretensioned AASTO Type VI girders,
and hide the fact that the bridge had dissimilar superstructure
cross-sections.
The main piers have a unique double-anchor shape that slims the
column yet still meet the demands of unshored, balanced cantilevered
construction. The ends of anchors have “tips” which
curl around to protect and hide light fixtures that illuminate the
bridge. Painted column webs are illuminated by 44 inexpensive induction-fluorescent
lights with a 20-year life-span, welcoming all to the Matagorda
Peninsula.
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Project Principals:
Owner: Texas Department of Transportation
Engineer: Dean Van Landuyt, P.E., Bridge Division,
Texas DOT
Construction Engineers: Summit Engineering Group
Inc. and
Frank W. Neal & Associates
Contractor: Midwest Foundation Corporation
Concrete Supplier: Alamo Concrete Products, Ltd.
Precast Concrete: Texas Concrete Company
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