Rehabilitation of Patroon Island Bridge Uses Lightweight Precast Elements

By Joe Kowalewski, Norlite LLC

In 2013, the New York State Department of Transportation (NYSDOT) undertook the project of repairing the Patroon Island Bridge in Albany, NY. The bridge carries Interstate 90 over the Hudson River between Albany andRensselaer counties and was originally built in 1968 with some structural repairs in 1992. This project involved rehabilitation of the bridge and all the ramps comprising the I-90 interchange with I-787. The bridge is constructed of ten spans, seven main spans which consist of steel trusses with concrete decking and three approach spans which are supported by plate girders. The structure’s overall length is 1,795 feet and the longest span is 375 feet with 60 feet of clearance over the Hudson River.

The project was part of the NYSDOT’s Accelerated Bridge Construction Program and a best-value procurement, not a low bid, so the contractors had to show NYSDOT how much disturbance of traffic would occur during construction. It was determined the use of precast elements would speed construction and minimize the traffic disruptions. Lightweight concrete made with ESCS aggregate was utilized in these elements to reduce the load on the structure, allow for ease of shipping and allow the use of a smaller crane on the project.

The Fort Miller Co., Inc. was contracted to cast a total of 1079 precast pieces (8800 cubic yards of lightweight concrete) of which 95%had a parapet cast integral with the deck and utilized the specified stainless steel rebar. With the complex geometry, Fort Miller’s internal engineering staffcreated all the shop drawings in-house. Ira Adler of Fort Miller developed a high performance lightweight concrete mix design in accordance with the guidelines set forth by NYSDOT. The high-performance lightweight concrete mix achieved release strengths of 3000 psi within 18 hours with an average 28-day strength in excess of 5000 psi. The specified lightweight concrete equilibrium density was 115 pounds per cubic foot.

The $148-million-dollar renovation and rebuild of the bridge was completed on May 31, 2016. The structure currently carries 70,000 motorists a day in the east-west direction over the bridge’s six lanes.

Owner:New York State Department of Transportation

Structural Engineer:HDR Inc.

Precast Supplier:The Fort Miller Co., Inc.

Lightweight Aggregate Producer:Norlite LLC

Contractor:Halmar International and A. Servidone-B. Anthony Construction Corp JV

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