Bridge HL-73 and Lake Louise Dam
Bridge HL-73 & Lake Louise Dam
The Reconstruction of Bridge HL-73 on Lanes Pond Road and Rehabilitation of Lake Louise Dam was a showcase of how a multidisciplinary firm’s versatility can save time and cost for a client. Lake Louise Dam is a high hazard dam due to potential for loss of life in the event of failure during low to medium frequency storm events. French & Parrello Associates (FPA) was responsible for design and construction support services for removing a single-span timber bridge and spillway structure and replacing it with a precast 3-sided frame bridge structure with cast-in-place spillway walls, founded on a pile-supported concrete mat foundation with steel sheet pile permanent cofferdams and temporary cofferdams.
FPA tackled the numerous facets of design that are presented when a roadway is also a dam, including spillway capacity and overtopping protection, embankment stability and seepage control in the form of permanent upstream and downstream sheet pile walls, bridge construction and highway design, and environmental permitting. In addition, FPA developed staging demolition for the removal of the existing bridge and spillway structure and staging for the installation of the bridge piles due to the proposed relocation sequence with overhead utilities.
Bridge Engineering and Design
Dam Engineering and Design
Roadway Design
Geotechnical Engineering
Permitting
Survey
Among the project’s unique aspects included the structure utilizing a pile-supported concrete mat foundation that supports the precast concrete 3-sided frame bridge and spillway; Removing all design exceptions from the proposed roadway design; Designing an ADA-accessible parking area and 6-foot, 6-inch wide sidewalk; and Designing a 3-sided drop box spillway with a low-flow notch to safely pass the 100 year flood event and providing overtopping protection through a downstream sheet pile wall designed to resist the forces of overtopping flow up to the 40% PMP event.
FPA designed the adequacy and condition of the spillway to meet Dam Safety Standards and prepared construction documents for the replacement and rehabilitation, in conjunction with removing the bridge structure and construction of the new bridge. FPA provided bridge engineering and design, dam engineering and design, and ancillary services, such as surveying, permitting, and geotechnical and roadway design, environmental impacts, ROW acquisitions, utility relocation, and cost estimates.
Recipient of the 2023 ACECNJ Engineering Excellence Grand Honor Award
