Innovative cable-stayed bridge opens in Texas
The Fred Hartman Bridge across the Houston Ship Channel in Texas opened this past September. With its symmetrically balanced towers and glistening arrays of cables, the facility conveys much about the art of contemporary structural engineering.
In terms of the surface area embodied in the twin 78-foot-wide decks, this cable-stayed bridge ranks as the nation’s largest and is surpassed worldwide only by a crossing still under construction in Japan.
The $92 million bridge is well on its way to becoming a Texas landmark.
The eight-lane bridge, which replaces the obsolete Baytown Tunnel, connects Loop 201 in Baytown with Texas Route 225 in La Porte.
More than a decade went into its planning. It has a capacity of 200,000 vehicles per day, nearly eight times that of the tunnel, which had been a traffic bottleneck for many years.
It is expected to serve as a conduit for the economic development of communities east of Houston.
Viewed from a distance, the bridge’s cables fan down to the decks off each side of the 435-foot-high towers. These suggested the golden chords of a harp to a columnist who was inspired recently to write about the crossing.
Even before that, others could see an “M” and “W” formed in the perfectly balanced profile of the double-diamond concrete towers poised so high that they seem to support the fog whenever it descends on the area.
To the engineers who design such monumental projects, the Fred Hartman Bridge was an unprecedented technical achievement that has advanced the design of cable-stayed bridges.
Some things, such as the tower and deck configurations, had never been tried before and were adopted only after certain theoretical design solutions were substantiated by comprehensive testing and computer simulations.
Technically, they deliver a “truss action” for greater lateral stiffness and work in tandem with the inward-sloping cables to torsionally resist unbalanced dynamic loadings imposed upon the decks.
Another strictly pragmatic goal of the design was to overcome poor site conditions on which the bridge stands as well as to gain the strength needed to withstand hurricane-force winds. The composite concrete poured into its decks was another unique application at the time of design.
The 1,250-foot-long steel main span, 482-foot-long anchor spans and 130 1/2-foot-long flanking spans were all designed by an engineering team with the Tampa, Fla., office of Greiner. The approaches were designed by engineers with the Texas Department of Transportation.
The design was funded by the Federal Highway Administration, which solicited alternate designs in steel and concrete for the main span.