Experimental, numerical, and theoretical studies for flexural resistance of steel beams with area losses

The present study conducts experimental, numerical and theoretical studies on the flexural resistance of rolled steel I-beams subjected to three distinct localized damage categories: bottom flange loss only, web loss only, and combined bottom flange and web loss. The effect of initial out-of-straightness, residual stresses, material and mechanical properties, area loss location and dimensions, and load location are considered in the present study. The experimental study quantifies significant effects of the area loss and its location on the system failure mode, resistance and deformations, simultaneously reports that the resistance is more influenced when the area loss occurs at the load location. The numerical study conducts 660 analyses for beams with various area loss scenarios and it reveals that the resistance variations of beams with a web or flange loss are high when the thickness loss increases within a range from 0.0 to 20%, those with both web and flange loss are high when the thickness loss increases within the ranges from 0.0 to 20% or from 80% to 100%, and those with flange and/or web loss are significant when the ratio of lost length/span length or lost web height/web height increases within a range from 0.0 to 10%. A simple design equation for the moment resistance is developed based on a standard design equation with introducing a new plastic moment and three regression factor groups corresponding to the damage types. The theoretical solution is successfully validated against available experimental, numerical and approximate results.