Steel wide-flange columns in existing truss bridges may be built-up with flange cover plate reinforcement to increase compressive capacity. This thesis investigates the use of partial-length steel cover plates about column mid-height to improve the weak-axis buckling resistance.
The present research first reviews literature concerning the Euler buckling of members with partial-length reinforcement. Inelastic buckling is simulated by 3-D finite element analysis accounting for cover plate length, cover plate area, bolt hole perforations, yield stresses, residual and locked-in dead load stresses, and initial out-of-straightness. The model is validated by a load test of a full-scale column with bolted reinforcement plates. A parametric sensitivity study shows that reinforced capacity is characterized by the transition between failure initiating either in the original column at the unreinforced end segments, or at column mid-height in the reinforced segment. An equation developed through multiple linear regression is proposed for a simplified procedure for preliminary design
