A study on ultimate flexural Behaviour of RC beams strengthened By external prestressing

Abstract

External prestressing is being successfully used for strengthening newlineexisting distressed concrete bridges Concrete beams new beams prestressed newlinewith external tendons are analytically treated as beams prestressed with newlineinternal unbonded tendons except the parameters associated with deviators newlineand anchorages However external prestressing technique needs special newlineattention when it is used for strengthening of distressed concrete structures newlineand bridges It is widely reported that external prestressing technique behaves newlinewell under service loads in post strengthening However the poststrengthening newlinebehaviour at ultimate state is uncertain which had been newlinereported elsewhere both in India and abroad It is necessary to predict the newlineultimate behaviour of concrete members strengthened by external newlineprestressing In view of the above a study has been carried out to investigate newlinethe ultimate flexural behaviour of RC beams strengthened by external newlineprestressing The ultimate flexural behaviour of members prestressed with newlineinternal unbonded post tensioning tendons also has been studied newlineRectangular RC beams were first loaded to have permanent cracks newlinewith strain in extreme compressive fiber in the range of 0 0005 to 0 0014 and newlinethe steel strain in the range of 0 0015 to 0 00275 In this study cracked RC newlinebeams were treated as distressed beams newline newline