In-plane behaviour of mono-symmetric tapered beams

• Conventional analysis incorrectly predicts shear stresses.
• Normal stresses are parallel to flanges, not centroidal axis.
• Parallel to flange assumption allows shear stress analysis.
• Shear stress magnitudes are controlled by gradient of flange forces.
• Calculated shear stresses are close to more accurate predictions.

Shear stress distributions in mono-symmetric tapered I-beams are incorrectly predicted by the conventional beam analysis method used for uniform beams. More accurate predictions are obtained by assuming that the normal stress trajectories vary linearly between plate edges, instead of parallel to the centroidal axis.Transverse shear stresses at the flange-web junctions of mono-symmetric tapered I-beams of constant depth are induced by gradients of the forces in the tapered flanges. The transverse shear stress distributions caused by axial force, moment, and shear force are constant, linear, and parabolic, respectively.Axial force induces non-zero principal axis shear stresses, while shear force induces non-zero normal stresses acting parallel to the centroidal axis.