Ductility enhancement of 60-m long span prestressed concrete girder using new high strength prestressed strands (2,160 and 2,400 MPa)

Abstract

In this study, quantitative evaluation on the enhancement in the ductility of 60-m long span prestressed concrete (PSC) girder to which the high-strength prestressed (PS) strands were applied will be made through the finite-element analysis. The extent of enhancement in the ductility was quantitatively evaluated by computing the deflection ductility index in accordance with the types of the PS strands. As the results of comparison with the deflection ductility index of PSC girder in which PS strands with a tensile strength of 1,860 MPa were used, the ductility was improved by about 1.38 folds when the PS strands with a tensile strength of 2,160 MPa are applied while there was approximately 1.71 folds enhancement in ductility when the PS strands with a tensile strength of 2,400 MPa were applied. In addition, the presence of large quantity of tendons can induce brittle failure of the girder due to the concrete fracturing in the compression region without the yielding of the PS strands. Therefore, it is necessary to reduce the quantity of tendons in order to prevent brittle failure and to secure the ductility, and, for this purpose, it is deemed appropriate to use high-strength PS strands.