Rehabilitation of I-90

This $145.8 million project rehabilitates the Patroon Island Bridge carrying I-90 over the Hudson River between Albany and Rensselaer counties. The project involved rehabilitation of the bridge and all the ramps comprising the I-90 interchange with I-787. Most of this work occurs during successive night closures of the bridge with no lane closures on I-90 during business hours. On I-787, lanes were shifted but not closed. The six-lane bridge maintained two lanes in one direction and one lane in the opposite direction throughout construction.

Under this assignment, SJH developed structural design and construction procedures for the demolition of the existing deck and the erection of precast deck panels for Spans 1, 2 and 3 of Bridge 5. The demolition drawings illustrate sequence of demolition, equipment location and method of removal. The existing framing was checked for structural adequacy to support equipment loading. We conducted a design investigation of the existing bridge structure to assess for 150-170 ton crane loads. Only night time or weekend closures were considered, and two panels were scheduled to be installed per shift. Our team provided two alternatives:

• Two cranes to be placed on the top of the bridge (Alternative #1), and
• One crane to be placed on the ground below the structure (Alternative #2)

Erection drawings featured panel layouts, crane locations, and the sequence of erection. The contractor selected from two alternatives that were developed for final design. Final designs with comply with AASHTO LRFD Bridge Design Specifications and AASHTO Manual for Bridge Evaluation. Construction was complete Summer 2016.