Rehabilitation of Distressed Concrete Beams Using External Prestressing - Experimental Study

摘要

Concrete structures showing distress due to one or more reasons; require remedial and strengthening measures, if the structure is to satisfy the serviceability and strength requirements. Provision of externally welded reinforcement to tension faces of RC flexural members and prestressing the same is proved to be an effective strengthening technique. This work reports the results of analytical and experimental study carried out on the use of this technique for strengthening and rehabilitation of distressed RC beams. Beams subjected to varying degrees of initial distress are strengthened with various levels of prestressing and tested to destruction. The performance of beams evaluated in terms of first crack load, stiffness characteristics, crack propagation, failure load, ultimate deflection, ductility and failure mode are discussed. The trussed beam exhibits delayed first crack. Stiffness characteristics of the beams are improved. Prestressing of tie rods also exhibits improvement in the load bearing capacity and stiffness characteristics. The load bearing capacity of the rehabilitated beam - the first crack load, service load as well as ultimate load - are increased considerably compared to the parent RC beams.