Washington Park Light Rail Station
The Washington Park Station of the Westside Light Rail Project was constructed on a deep-seated ancient landslide. Initial excavation for the station headhouse reactivated a portion of the ancient landslide. Excavation was temporarily halted after Landslide Technology determined that a local slope failure would likely occur during continued excavation.
In association with Parsons Brinckerhoff, Landslide Technology performed an investigation of the reactivated ancient landslide and developed a practical solution to provide resistance against sliding at a very low cost. Piles that were initially designed as the foundation support for the station headhouse were modified to resist the lateral forces of the deep landslide. A line of piles on the uphill side of the excavation was redesigned as heavily reinforced concrete shear piles.
A landslide monitoring system was designed, installed and implemented by Landslide Technology to closely monitor the reactivated ground movement and to allow construction to continue. In addition, Landslide Technology developed a long-term landslide monitoring plan using an automatic data acquisition system of in-place inclinometers, multiple-level piezometers and a rain gauge. The automated system allowed a critical “threshold movement rate” to be established in the event of reactivated ground movements.
This landslide remediation won the Project of the Year Award in ACEC Oregon Engineering Excellence competition.