Strength and ductility prediction of concrete beams reinforced with internal steel and external composite materials

Abstract

Reinforced concrete structures undergo continuous deterioration throughout their service life, and many are required to support loads exceeding in initial design loads. Such structures need to be replaced or rehabilitated, with rehabilitation being the cheapest alternative. There are currently a number of techniques available for rehabilitating structural members in functionally obsolete or structurally deficient structures. One such rehabilitation method, getting particular attention during the last decade, is the use of externally bonded fibre reinforced polymers strips to increase or restore load capacity of structurally deficient or functionally obsolete beam, column and slab members. To design for team rehabilitation, it is fundamentally important that the expected increase in capacity due to the fibre reinforced polymer strip is quantified. In this paper, a simple computational model that predicts the linear and nonlinear behaviour of a fibre reinforced polymer rehabilitated reinforced beam is presented. The model has been implemented in Matrix Laboratory software package. The mode: quantifies the moment-curvature and load-deflection relationships. The model is verified by comparing numerical results with experimental data for fibre reinforced polymer rehabilitated beams. The results of a parametric study investigating the influence of tensile steel reinforcement and composite reinforcement (carbon or glass fibres) are presented.