Valley Line LRT Construction Update

EDMONTON, AB – March 15, 2018 – While undertaking foundation construction for the new Tawatinâ Bridge, TransEd crews working on the north side of the North Saskatchewan River have encountered an unforeseen challenge. This has caused construction delays.

In order to construct a pier in the river to support the new bridge, “steel sheet pile cofferdams” are used. Cofferdams work much like a window well in your home: the cofferdam is a temporary enclosure that holds back water, which permits construction work below the river line. This  allows for safe construction of the bridge’s pier and foundation.

TransEd undertook cofferdam construction and encountered an unknown obstacle in the process that prevented completion of the cofferdam. Follow up investigation determined that the obstacle was a large concrete obstruction. Both TransEd and the City’s documents and prior geotechnical investigations did not identify an obstruction in that location.  The obstruction is about nine metres below the surface and its full extent is currently unknown.

Due to both safety and environmental considerations, investigative work continues cautiously to avoid any danger to workers and the river valley. TransEd has brought in several experts to develop a safe technical solution. These experts have worked on and managed cofferdam construction all over the world, in a range of environments including the ocean. They will advise on how to modify the cofferdam to allow for the safe excavation down to the required bridge foundation depth.  

At this time, TransEd can confirm that the opening of a Shared Use Path, as part of the new Tawatinâ Bridge, will be delayed past the original scheduled opening in May 2019.

TransEd and the City are working together to mitigate impacts from this difficulty and are optimistic they will find a solution to meet the safe and timely delivery of the project.

Work in this area continues to advance and TransEd will provide updates as we work to find a resolution to these challenges. Meanwhile, progress across the remainder of the Valley Line LRT Project has continued throughout the winter season and will ramp up further this Spring. 

Later this spring, we will be celebrating the completion of tunnel excavations. Details will follow within the next few weeks.

A series of open houses will be held in communities along the alignment to provide an update on spring construction and answer questions.