I-95 Northbound Viaduct Replacement

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The project consisted of replacing the I-95 Northbound Viaduct through the heart of downtown Providence, RI, spanning over the Woonasquatucket River, Amtrack Northeast Corridor, city roads, and interchange ramps. Several interchange ramps and overpasses were also replaced as part of the project. Underpinning & Foundation Skanska (UFS) installed deep foundations and support of excavation systems for the project.

The deep foundation scope of work consisted of both driven and drilled piles for the mainline piers and foundations. The driven pile work consisted of driving steel H-piles to bedrock at depths of up to 150-feet. The drilled pile scope consisted of both vertical and battered 12-inch diameter micropiles drilled up to 160 feet deep and socketed into bedrock at mainline piers and abutments. Additional micropiles were installed at other locations on the project to provide foundation support for both new and existing structures. 

The support of excavation scope of work for permanent structures consisted of both driven and drilled soldier pile walls along Park Street and tie-back anchors installed through existing abutments that were incorporated into the final structures. Site constraints and geotechnical conditions varied across the project requiring UFS to install various temporary support of excavation systems including internally braced sheet pile cofferdams, and soldier pile and lagging walls. In a unique application, UFS utilized existing battered H-piles, originally installed to support the viaduct north abutment, as soldier piles. Lagging was installed between the H-piles and multiple layers of tiebacks and walers were installed to provide lateral restraint to the piles.  The resulting system facilitated excavation for the installation of the new foundation structure while continuing to support the existing abutment.

In addition to the installation of deep foundations and support of excavation systems, UFS assisted in project development prior to award, along with pre-construction planning prior to the commencing construction.