-Making something old, new again-
City begins work to restore historic Presa Street Bridge

Beginning today, Presa Street will be closed to through traffic between Market and Villita streets as the City begins work to restore the Presa St. Bridge. Traffic will be able to access Presa from Nueva.

The bridge will undergo rust removal and a thorough cleaning process. Work on the bridge will be conducted above and below street level and will address abatement of existing lead-containing base coatings, spot treatments of limited corrosion and other minor repairs. The repairs and repainting will create an updated appearance and ensure protection of the structure. The bridge will be stripped of existing paint and repainted black in accordance with approvals from the State Historic Preservation Office. Construction on the Presa St. Bridge is anticipated to be complete by November 2009. Funds for this project were provided from 2007 Downtown Infrastructure bonds and Certificates of Obligation.

Erected in 1890, the Presa St. Bridge remains at its original site on South Presa between Nueva and Market streets. The bridge was manufactured by the Berlin Iron Bridge Co. of East Berlin, Connecticut. It is one of three Berlin bridges that remain on the San Antonio River Walk.

One of the features that attracted the City of San Antonio to the Berlin Iron Bridge Co. was the company’s ability to incorporate Victorian design flourishes in its work. These details are evident in the iron lattice work and cast-iron rosettes that decorate the Presa Bridge railings.

The Berlin Iron Bridge Co. fabricated nearly all of its bridges out of wrought iron. It wasn’t until later in the decade that steel, which was twice as strong, replaced iron as the primary material used for bridge construction. The strength of each Berlin Iron bridge would be ceremoniously tested at each dedication event, when a fifteen-ton steamroller was driven onto the bridge. Today, it is estimated that nearly 3,000 cars a day travel across the Presa St. Bridge.

Another feature of the Presa St. Bridge is its use of iron pins to join the connecting beams. Nineteenth century engineers believed that pins rather than riveted connections helped distribute force more evenly. The bridge is an example of a lenticular pony truss bridge, which the Berlin Iron Bridge Co. was known for producing. The term “lenticular” refers to the curved shape of both the top and bottom chords of the bridge. This made the middle of the bridge the deepest, and therefore the strongest, point. Pony truss bridges were typically used for bridges with a maximum span of 100 feet, which includes the Presa St. Bridge. Due to the shorter span, these bridges did not need reinforced bracing and are therefore open at the top.

San Antonio is unique in that it is home to four intact Berlin Iron bridges. The Augusta and Crockett street bridges remain downtown. The fourth bridge, originally located on St. Mary’s St., is now at home in Brackenridge Park.