Temporary Excavation Support System for a New Railway Bridge and Highway Underpass in Pittsburgh

Until recently, traffic exiting Pittsburgh would use the West End Bridge to cross the Ohio River only to become entangled in the West End Circle, which consisted of two railway overpasses each out-of-alignment with the West End Bridge. A roadway improvement project involving the construction of a new railway bridge and highway underpass was undertaken to eliminate this traffic circle and provide a direct connection between the West End Bridge and State Route 19. Brayman Construction Corporation has since completed this project. This paper provides a summary of the design and construction sequencing of a temporary sheet pile excavation support system that was constructed to facilitate the completion of this project. The excavation support system consisted of opposing sheet pile walls (shoring and anchor walls) cross-tied with prestressed tendons beneath the railroad corridor. The general arrangement of this system is shown in Figure 1. The prestressed tendons limited the horizontal wall displacement to permissible levels specified by the railway owner, and the reuse of the phase one shoring wall as the shoring wall for the second phase of bridge construction eliminated the need to extract and re-drive sheeting, resulting in reduced displacements and construction time.