Full-range analysis of shear-lag effect in reinforced concrete T-beams considering rebar corrosion

To investigate rebar corrosion influence on full-range shear lag of RC T-beams, an equivalent formula for non-uniformly corroded sections was established based on experiments and bond-slip degradation theory. Combined with the energy variational method, an analytical solution for shear lag was derived. A modified effective flange width calculation, accounting for width-to-span ratio and corrosion coupling, was proposed using nonlinear least squares. The analytical solutions agreed well with experimental and FE results. For deteriorated simply supported T-beams, maximum stress difference ratios with experiment and FE are 20% and 15%; for continuous beams, the difference with FE is 14%. With increasing corrosion rate, the Reissner parameter and shear lag-induced additional deflection decrease for full sections but increase for cracked sections. At 10% corrosion, the Reissner parameter difference ratios for full and cracked sections are 2.2% and 11.2%. Similarly, the shear lag coefficient and its difference ratio increase with corrosion; at 10%, the ratios are 2.82% and 4.44%. The effective flange width correction factor increases as width-to-span ratio decreases, but decreases as rebar corrosion increases. Compared with code-specified methods, correction factors from the reduction method (RM) and the theoretical method (TM) agree well, demonstrating satisfactory computational accuracy.