Experimental evaluation of compressive behavior of orthotropic steel plates for the new San Francisco Oakland Bay Bridge

Abstract

Compression tests were conducted on two reduced-scale orthotropic plates to verify the design strength of steel box girders for the new San Francisco-Oakland Bay Bridge. The first specimen was composed of three longitudinal closed ribs and a top deck plate. It failed in global buckling, followed by local buckling in the deck plate and ribs. The second specimen, which was composed of four longitudinal T-shaped ribs and a bottom deck plate, experienced global buckling as well as local buckling in the ribs and the deck plate. The ultimate strength and failure mode of both specimens were evaluated by two bridge design specifications: the 1998 AASHTO load and resistance factor design specification and the 2002 Japanese JRA specification. Findings from code comparisons showed that: (1) Sufficient flexural rigidity of ribs were provided for both specimens; (2) the JRA specification slightly overestimated the ultimate strength of both specimens; and (3) neither specifications predicted the observed buckling sequence in Specimen 2. A general-purpose nonlinear finite element analysis program (ABAQUS) was used to perform correlation study. The analysis showed that the ultimate strength and postbuckling behavior of the specimens could be reliably predicted when both the effects of residual stresses and initial geometric imperfections were considered in the model.