This project is part of the Eglinton Crosstown LRT in Toronto. A launch shaft was constructed for tunnel boring at 2015. The shaft is approximately 130 m long, its width varies from 14 to 19 m and the excavation depth varies from 9 to 13 m. The shoring is a secant pile wall with various anchor tieback levels. Along the north boundary, the shoring retains Eglinton Street. The LRT project requires the removal of all existing anchor tiebacks of the temporary shoring prior to the construction of the inner tunnel structure.
Pedelta has been retained to provide a solution for the anchor tieback removal and demolition of the east boundary shoring. Several construction approaches have been assessed to provide the most efficient way to remove the tiebacks without affecting the construction of the internal structure. Pedelta has define the build-back staging, and designed temporary bracing (struts and rakers). To overcome the construction challenges, dedicated two-dimensional structural analyses were used for modeling the construction sequence and anchor removal. A comprehensive monitoring plan was defined to control movements, tieback forces and deformations of the shoring during anchor removal.