Because of increasing live loads and structural deterioration, appropriate methods ofrehabilitation are essential for extending the lifespan of bridges and buildings. To strengthen existingstructures, externally bonded and un-bonded strengthening methods have been studied and applied tosites over the last two decades. Independent research of these two general methods has been on-goingintensively; however direct comparisons between them have been rarely reported. The aim of this paper isto suggest appropriate strengthening applications by comparing these two methods. To provide anappropriate representation of behaviour, the behaviour of the different strengthening systems wasmodeled using a commercial finite element software, ANSYS. To study the effects of the twostrengthening methods, four small-scale (1.8 m span) reinforced concrete beams were strengthened bydifferent ways employing a CFRP sheet (bonded) and prestressed steel tendons (un-bonded) with andwithout eccentricities. These beams were tested experimentally and their behaviours to failure werecomputationally simulated. The experimental and the computational results showed good agreement (i.e.moment-curvature behaviour and dynamic crack propagations). The results indicated that the CFRPattached case was the most effective strengthening method to increase the ultimate strength of the beam.However, the beam strengthened by un-bonded prestressed steel tendons applied with eccentricityshowed the most suitable strengthening effect in the service loading range.
展开▼
