Historic bridge survey update
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Historic bridge survey update

Workers constructing a new bridge over the Colorado River at Lohman’s Crossing in Travis County in the 1930s. Photo: Austin History Center, Austin Public Library PICA 18679

Did you know that TxDOT inspects over 55,000 bridges across the state? When bridges need repair or need to be replaced, TxDOT must assess the historical significance of the bridge before approving the project. Since there are so many bridges in Texas, TxDOT developed a systematic way to evaluate them by dividing them into groups. For example; TxDOT completed studies of truss bridges and bridges built between 1945-1965.

These studies require updates from time to time. TxDOT’s latest update re-assesses the historical significance of the state’s “non-truss” bridges constructed before 1946. What is a non-truss bridge? It is one that supports its load in a way other than a series of triangles joined together. These bridges come in a variety of shapes (arches, beams, and slabs), materials, and sizes. They were a common choice in Texas from 1905 to 1955.

TxDOT’s Non-Truss Bridge (NTB) update will:

  • Update TxDOT’s data records for individual bridges of this type (approximately 6,500 structures).
  • Expand our understanding of why bridges of this type, and of this era, are important.
  • Establish a reliable process to evaluate the historical significance of this population of bridges that looks beyond architecture and engineering.

TxDOT needs your help to determine what makes these non-truss bridges special. Visit our Interactive Comment Map to tell us the history of a bridge, or share stories or pictures.

What is a truss bridge?

Truss bridges use a framework of structural members in a series of triangles joined together to carry heavy loads. With a single exception in Texas, truss bridges are both metal and constructed to a variety of designs. Click here to know more about truss bridges.

The 1940 bridge carrying US 190 over the Colorado River in Lampasas County is an example of a truss bridge.
Detail of railing on bridge carrying US 79 over Mustang Creek in Williamson County, 1939

Bridges aren’t just important for engineering. They tell stories about:

  • National trends in transportation such as building bridges to separate roadway and railroad crossings.
  • The development of cities.
  • Shaping the identity of communities.

Information from local communities helps TxDOT understand why a bridge may be important. The Non-Truss Bridge (NTB) update will develop a methodology for learning about bridge significance related to important events, trends, and people. TxDOT will use tools like interactive workshops, maps, and stakeholder collaboration to design and test the methodology.

Questions and Comments? Contact: Mark Brown, Project Manager

Paddock Viaduct, Fort Worth, 1914. Photo: HAER TX-50