Lundeen Parkway Extension Bridge*
Lundeen Parkway Extension Bridge
TranTech engineers, Kash Nikzad and Theo Trochalakis were the Project Manager and Senior Structural Engineer on this project. The Lundeen Bridge is a part of a 2,750-meter-long extension and improvement of the Lundeen Parkway in Snohomish County. The project widens the roadway to a 4-lane facility that extends between SR9 and SR 204 with Class 2 bike lanes and sidewalks on both sides. The roadway crosses a steep ravine. One of the responsibilities was to prepare PS&E documents for the bridge that carries Lundeen Parkway over the ravine. The single-span bridge is approximately 53 meters long (i.e 174 feet) and 15.5 meters wide (i.e. 51 feet). The bridge’s superstructure is composed of five steel plate girders that are 7-feet deep spaced at 3.1 meters (i.e. 10 feet) and made composite with an 8 1/2-inch cast-in-place deck. The substructure is composed of abutments founded on 4-foot diameter drilled shafts that extend 70 feet below existing ground line. The top layer of soil in the ravine is composed of fill/loosed material. Both engineers worked closely with the County’s in-house geotechnical experts to solve this issue by using Control Density Fill at the abutment locations. The abutments are intentionally designed wider (i.e. 70 feet) for future Parkway widening considerations.