Section 3: Railing on Historic Bridges
Anchor: #i999673Additional Guidelines
Federal law protects historically significant bridges, and any rehabilitation or improvement projects on them require special attention. Bridges that are designated historic and that are listed or eligible to be listed in the National Register of Historic Places introduce a special railing challenge because the appearance of the bridge may be protected even though the historic railing may not meet current standards. As soon as a project is determined to involve a historically significant bridge, the district should contact the TxDOT Bridge Division, as directed in the Bridge Division’s Historic Bridge Manual. The director of the Texas Historical Commission is the designated State Historic Preservation Officer (SHPO) for Texas, and the SHPO and TxDOT are responsible for determining what effect any proposed project will have on a historic bridge.
Anchor: #i999687Historic Bridge Railing Options
Original railing on a historic bridge is likely not to meet current crash-test requirements. It also is likely not to meet current standards for railing height (a minimum of 27 inches) and for limits on the size of openings in the railing (small enough that a 6-inch sphere cannot pass through them). Options for upgrading the railing on historic bridges usually include the following:
- Place an approved traffic railing inboard of the existing railing, leaving the existing railing in place. This is sometimes appropriate when a pedestrian walkway exists on or is planned for the bridge.
- Replace the existing railing with an acceptable approved railing. Possible close matches include Types T401, T402, or C402 and T411 or C411.
- Remove the current railing and incorporate it into a new acceptable railing. This may be appropriate in rare instances where an existing railing is especially decorative.
- Design a special railing to match the appearance of the existing railing. It may not be necessary to crash test the new railing if the geometry and calculated strength equal or exceed a crash-tested railing.