Burlington Skyway, Ontario, Canada

This 2,560 m long steel bridge built in the mid 50’s was repaired and strengthened in order to increase the number of lanes from four to five and to support the heavier design loads of the current codes.

The three main spans (84-151-84 m) consist of a continuous truss arch structure where the two longitudinal main trusses are connected by bracing bents and transverse floor trusses. These trusses support longitudinal deck stringers, which in turn support a reinforced concrete deck. The transverse floor trusses consist of standard structural steel shapes riveted and bolted together. The increased loading resulted in significant overstressing of the transverse floor truss members. These trusses were strengthened by external post-tensioning using Ø36 mm DYWIDAG bars (THREADBAR ^®) and a limited addition of new structural steel. This method allowed a minimal number of members to be dismantled and eliminated the need for strict dimensional tolerances that would be required with the addition or replacement of truss members. The selected draped tendons were anchored in the deck slab to maximize their effectiveness. A unique steel plate assembly was bolted to the truss joint at the deviation point of the tendon to anchor the bars and transfer the tendon force to the truss. The bars were protected by a three-coat zinc/vinyl paint system.