Experimental testing of concrete beams with different levels of prestressing

Abstract

The behaviour of actual prestressed concrete beams under static load up to failure has been experimentally investigated. The experimental testing includes five types of precast concrete beams with different ratios of prestressed and classical reinforcements (only prestressed reinforcement, dominant prestressed reinforcement and classical reinforcement, equal prestressed and classical reinforcements, dominant classical reinforcement and prestressed reinforcement, and only classical reinforcement) i.e. with different levels of prestressing force. Twenty-three beams were tested. The total amount of reinforcement in each beam was selected to provide approximately equal ultimate bending bearing capacity. The deflections, concrete stresses, stresses in classical and prestressed reinforcements and concrete cracks were monitored until the beams collapsed. It was concluded that by increasing the level of prestressing, the serviceability limit state of the beams was improved. The optimal level of prestressing should be selected based on the relevant criteria for each individual structure.