One of the many Texas Engineering Landmarks in celebration of Texas ASCE’s Centennial: 1913-2013 “Engineering a Better Texas.” Visit them all!
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IN A THUMBNAIL:
Declared a Texas Historical Civil Engineering Landmark on March 28, 2001, in 2002 the Hays Street Bridge is really two different kinds of truss spans: Pratt & Whipple. It was the 150th Anniversary Project for both the Texas ASCE & the San Antonio Branch, rehabilitated into a pedestrian and bicycle crossing over active railroad tracks on the eastern edge of downtown San Antonio, TX. Posted to the National Register of Historic Places on September 10, 2012.
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The Hays Street Bridge’s history goes back to 1881, when the Galveston, Harrisburg, and San Antonio (GH&SA) Railway was pushing west from San Antonio. The contract for the numerous bridge spans was given to the Phoenix Bridge Co. of Pennsylvania, who built these roughly 16-foot wide Pratt and Whipple truss spans to span the Nueces River west of Uvalde. In the early 1900s the GH&SA Railroad wanted to cross all of the east-west streets of the Eastside of San Antonio with their main lines. The City, for its part, required them to provide a 25-foot-wide viaduct at Hays Street for pedestrians and vehicles, assuring a full-time connection between the Eastside and Downtown.
In 1910 the railroad relocated the spans you see here from the Nueces River to San Antonio (there is some contention that the two spans came from different bridges, according to the Bridge Hunter website – reference below) to provide the required viaduct. Not a mean feat in itself, but ultimately easier than building from scratch.
Truss bridges were widely used from the 1870s to the 1930s. The Hays Street Bridge utilizes truss spans of two designs: the Pratt and the Murphy-Whipple. The two sections appear noticeably different. The shorter of the two (at 130 feet) is the Pratt design, pioneered in 1844 by Caleb Pratt and his son Thomas. Considered simple yet efficient, its familiarity even extends to the wing design for the first successful Wright Brothers airplane. The 225-foot Murphy-Whipple section is a modification of the Whipple Truss by John Murphy of the Lehigh Valley Railroad. The Murphy-Whipple concept was further modified to include a Phoenix patent design using the now rare Phoenix segmental wrought iron columns with cast-iron joint blocks. (Which were apparently surprisingly durable, according to Sparks Engineering, ASCE Structures Conference article referenced below.) The Pratt span also has Phoenix-branded components, including the floor beams.
As part of the relocation, the spans were widened in 1910 to the current 25-feet per City request.
Most of the bridge’s early traffic was horse drawn, and early travelers across the bridge recalled the rhythmic clatter of floor boards as they drove across. As vehicles became heavier, the boards were covered with two to three inches of asphalt.
The bridge was closed to traffic in 1982 and left essentially a derelict until, in the 1990s, Douglas Steadman, P.E. (formerly president of W. E. Simpson Company in San Antonio) identified the bridge as historically significant and successfully obtained Texas Civil Engineering Landmark status for the two trusses. Mr. Steadman also led the effort to obtain grant funding and private contributions to save the bridge. The City of San Antonio, using a Transportation Enhancement grant from the Texas Department of Transportation chose to rehabilitate the bridge into the pedestrian/bicycle crossing you see today. Sparks Engineering, Inc. of Round Rock was the design consultant for the project and in 2010 this stately old bridge was reopened to the public.
VITAL STATISTICS:
225 ft. Whipple-Phoenix span
130 ft. Pratt span
1,045 linear feet concrete approaches
1,400 ft. total bridge length
Reference/Further Reading:
“Rehabilitation of the Historic Hays Street Viaduct in San Antonio,
Texas” S. Patrick Sparks, Sparks Engineering, Inc., Round Rock, Texas
psparks@sparksengineering.com; Procedings of the ASCE Structures Congress 2009 (
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“San Antonio’s Old Hays Street Bridge- Restoration Underway” TCE, Winter 2009 (
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Bridge Hunter: Hays Street Bridge (
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Hays Street Bridge Yelp (
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Hays Street Bridge Landmark facebook (
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Other waymarks:
Hays Street Bridge - San Antonio, TX, USA in Truss Bridges (
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