On Nov. 5, the Pagosa Springs Town Council offered direction to town staff on how the council would like to move forward with the planned 1st Street pedestrian bridge.
Town Projects Manager David Hilborn presented three design choices that would maintain pedestrian viewing capability as well as other important design features of the bridge.
Hilborn explained that town staff and project consultants realized that the installation of necessary utility lines (water, sewer, electrical and fiber conduits) under the bridge’s deck, along with floodway clearance requirements and ADA trail tie-in considerations, increased the current bridge top chord height, which would obstruct pedestrian views over the railing.
The three options presented were aimed at addressing this issue, with Hilborn explaining that town staff recommended an option to utilize a bowstring-style truss with a concrete deck.
This option provides “greater structural capacity, accommodating the weight of utilities and the concrete deck,” as well as reducing “the chord height … on both ends of the deck, with pedestrian viewing ‘windows’ in the middle of the bridge,” an agenda document states.
Hilborn added that this option is also ideal because it adds “no additional budgetary impact compared to the original design, and no increase in long-term ownership costs.”
He noted that this style would deviate from the Pratt-style truss bridges with wooden decks seen elsewhere through town, but the new style is ideal because the concrete deck would last a lot longer than wood and has “no budgetary impact.”
Council member Gary Williams asked what the life expectancy of a concrete deck would be, with Hilborn answering that it would last about 40 years.
Council member Brooks Lindner suggested he is not too concerned about the bridge deviating from the style design of other town bridges, asking his fellow council members if any one else has any issue with this inconsistency.
Mayor Shari Pierce noted that it is “not worth it” to pay extra money for making it consistent with the other bridges.
Council member Matt DeGuise added that he actually prefers a concrete deck, saying that wooden decks on bridges get super slippery when iced over.
An agenda document on the matter states that the bowstring-truss option “meets all project requirements— accommodating the added weight from utility lines and the concrete deck—without increasing the project’s budget.
“Additionally, the design’s structural efficiency minimizes material use, while still providing optimal pedestrian viewing.”
When a motion was made to direct town staff to pursue the bowstring-truss design option for the bridge, it was passed unanimously by the council.
Council members Madeline Bergon and Mat deGraaf were absent from the meeting.
derek@pagosasun.com
