The American Concrete Institute recognized the RLW team with their 2014 Excellence in Concrete Award for the SH-55 over the North Fork of the Payette River project. Congratulations to all RLW team members who contributed to another successful project!
The existing five-span bridge carrying SH-55 over the North Fork of the Payette River was deteriorating and in need of replacement. RLW and Lochner, working in a design-build team with the Idaho Transportation Department (ITD), replaced the existing bridge with a new 200-foot long single span bridge. The new structure is 54 feet wide and includes two 12-foot lanes, as well as six-foot bike lanes and sidewalks on both sides of the bridge. The bridge also features a belvedere, which is 52 feet long by seven feet wide, that overlooks Payette Lake. Using the design-build process, the team elected to use a concrete structure for the bridge in order to obtain the highest value for the project budget. The agency had achieved previous success with concrete bridges and recognized their ability to reduce long-term maintenance costs and extend the durability of the bridge decks.
There were several factors that made concrete the best choice for the Lardo Bridge replacement:
-Faster fabrication and delivery speed
-Robust prestressed/precast section was best suited to resist the lateral forces for the eight foot pedestrian overlook
-The versatility of the concrete enabled the designer to have more freedom in the placement of corbels and diaphagms required to transfer the overlook loads
SH 55 is the primary critical roadway in the City of McCall’s network. In order for this project to be successful, it was critical that construction minimized disruption to traffic. The team used an Accelerated Bridge Construction (ABC) technique known as a “lateral slide” to keep traffic flowing during construction. The new bridge was built on temporary abutments adjacent to the existing bridge and slid into place when the existing bridge was demolished. By working together to design and construct a bridge that could be constructed with this method, the team was able to reduce amount of time that traffic was impacted by this project by months.
Because this project included no aesthetic requirements, the team worked closely with the City of McCall to develop aesthetic concepts for the bridge that met their goals, accommodated the design specifications, and integrated into the overall project budget. Ultimately, the team used exposed concrete with simple, yet elegant patterns, painted railings, and arched concrete features under the belvedere.
Other portions of this project included roadway rehabilitations and sewer system replacements and upgrades.
Because the demolition and construction occurred over the Payette River, RLW used careful environmental controls to avoid pollution and environmental impacts.