This paper is a report on the results of studies about post-tensioned unbonded prestressed concrete beams. Based on experimental and analytical studies of flexural behavior and ultimate strength of beams, the relative performances of various types of post-tensioned prestressed concrete beams are compared. Test results of 8 rectangular beams are given, involving (1) two post-tensioned bonded prestressed concrete beams using normal concrete (2) two post-tensioned unbonded prestressed concrete beams using normal concrete (3) two post-tensioned bonded prestressed concrete beams using lightweight concrete (4) two post-tensioned unbonded prestressed concrete beams using lightweight concrete. The characteristics of four types of post-tensioned beams are compared in terms of load-strain relationships, load-defiection relationships flexural rigidity, and ultimate strength of beams failing in flexure.
