The Lincoln Tunnel Helix, the roadway to connect major New Jersey highways to the Lincoln Tunnel, was constructed in 1937 and now is one of the busiest crossings in the world, carrying over 38 million vehicles per year [Port Authority NY NJ]. The aging and deteriorated structure was required to be replaced with a new roadway that met current highway and safety standards. CHI performed conceptual design of girders, cross frames, and pier caps and stability analysis of the existing bridge at construction stages. 

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At the conceptual design, different design concepts by locations have been presented to resolve vertical clearance issues of some locations. Structure sizes based on the proposed design concepts were refined in the structure analysis program, Midas Civil. The structural analysis was performed based on AASHTO LRFD and regional design standard. Specifically, for live load analysis, local commuter buses (PABT Bus) as well as AASHTO Standard trucks had been considered. CHI also performed stability analysis of the rest parts when the parts of the existing structure were demolished. For the stability analysis, the 3D finite element model was developed based on the inspection and maintenance history.