Improved uncoupled closed-form solution for adhesive stresses in plated beams based on Timoshenko beam theory

Abstract

Premature failure due to plate-end debonding or plate-end separation can take place in reinforced concrete (RC) beams with a bonded plate at soffit, which results from concentration of adhesive stresses at the plate ends. Many theoretical studies based on the Euler-Bernoulli beam theory for simply supported beams bonded with plates and subjected to a partial load have been conducted to investigate the adhesive stresses. However, the results of these studies lack accuracy especially for depth beams because shear deformation in the plate and the beam is neglected. Only a few studies have considered the effect of shear deformation of both the plate and the beam, but the general solutions and problem solving procedures are extremely complicated owing to the fact that the two governing equations for the normal and shear adhesive stresses are coupled. In this paper, a new theoretical method is proposed to derive two uncoupled governing equations, and the exact general solutions are obtained. The proposed model is validated through comparisons of the adhesive stresses evaluated with another two existing models and measured from test. The effects of elastic modulus of the adhesive and plate, thickness of the adhesive and plate, and length of the bonded plate on adhesive stresses are investigated with the proposed and validated model, from which useful conclusions are provided for potential applications.