The open rib steel orthotropic decks in the upper-level roadway of the George Washington Bridge have been carrying an enormous amount of heavy trucks, therefore experienced a large number of fatigue cracking, especially in their rib-to-sub floorbeam welded connections.

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Under this project, CHI performed detailed finite element modeling and analysis to determine the causes of fatigue cracking and evaluate and compare different retrofit options. In these local models of the steel orthotropic deck, the deck details, including plates, welds and bolts are modeled using 3D solid elements in the CalculiX program. The contract behaviors between various steel elements are also captured through nonlinear contact elements. CHI performed nonlinear contact analysis for the existing condition, as well several retrofit options, including bolted flanges. In the end, a summary report was prepared with recommendations for future retrofits.