ABSTRACT
Experimental research is carried out to investigate the influence of preloading on the stability of the axially compressed members strengthened under load. Six specimens are involved, including an unstrengthened member and five members strengthened under different preloading magnitudes. The member to be strengthened has a welded H-shaped section. Four steel angles are bolted to the H-section to strengthen the member. All the six specimens fail in a flexural-torsional buckling way, in which the bending deformation is dominant. Test results indicate that preloading has little effect on ultimate capacity when strengthening is implemented in the elastic stage.
