TRANSFER LENGTH AND PRESTRESSING EFFECTIVE RATIO OF STEEL STRAND FOR PRESTRESSED CONCRETE AFTER 7 YEARS FROM PRESTRESSING

The transfer length and prestressing effective ratio were reported when prestress was introduced at the center of the cross section of the member using pre-tension method using steel strand for prestressed concrete. The transfer length of the indented steel strand for prestressed concrete was about 50 to 60% of that of the normal one. The transfer length was generally constant after 1 to 2 years after prestressing. It was possible to roughly estimate the prestressing effective ratio using existing calculation methods. The prestressing effective ratio fell slightly below the calculated value after about three years from prestressing.