DIRECT METHOD FOR ESTIMATING PRESTRESS LOSSES

A rational method for estimating prestress losses in pretensioned concrete members is presented. The method is based on linking experimentally developed stress-strain-time relationships of steel and concrete materials. It enables a direct determination of stress and strain distributions in a member at any time within the service life of the member and avoids the need for step-by-step methods. Wide ranges of variation for concrete material characteristics and other design factors are permitted. The new method is illustrated by a practical design problem. Comparisons with 2 recently proposed procedures show good agreement of results.