Web Buckle at I-40 Bridge Test

Abstract

An unexpected, but explainable, web buckle occurred during the field testing of the I-40 bridge over the Rio Grande in Albuquerque, N.M. The three-span continuous steel plate-girder bridge had a defect (physical cut) introduced at the midpoint of one of the center span girders that led to the buckle. The buckle can be attributed to the bending stress being released during the imposition of the defect into the plate girder, which in turn created a vertical compressive stress in the web sufficient to buckle the web. Classical buckling and strength of materials equations are utilized to explain the observed phenomenon. A finite-element model supports the deduction.