The Analytical Study of Strengthening the Bottom Flange of Steel I-Section Simply Supported Horizontally Curved Beams

Abstract

This research is devoted to study the effects of strengthening the bottom flange of steel I-section simply supported horizontally curved beams on the behavior and maximum strength of these beams under concentrated static load. The strengthening includes increasing the thickness of bottom flange at finite region (angle of strengthening,(φ)), thus the volume of steel will be increased. Three dimensional nonlinear finite element analyses done utilizing computer program called NFHCBSL, incorporate 20-node isoparametric brick element used to represent the steel elements. The study incorporates five angles of horizontal curvature (0=5o,10o,15o,30o and 45o). For each angle of horizontal curvature , eight regions of strengthening investigated, thus forty case had been studied. The results show that by strengthening the bottom flange of this type of beams the ultimate strength of beam can be increased about 35%, while the maximum vertical and the horizontal deflections can be reduced by 67% and 69% respectively, when the angle of strengthening (φ = ,i.e. the increment in the volume of steel is equal to 15.7%). Also, when the angle of horizontal curvature( ) increases the ultimate strength of beam decreases for any value of angle of strengthening (φ), but this decrement increase rapidly if the angle of strengthening (φ) was increased.-*