Strength of prestressed concrete members at sections where strands are not fully developed

In some precast, prestressed concrete flexural members, prestressing strands may not be completely developed at sections of high moment. This situation can be particularly critical when some of the strands are debonded near the ends of the member to reduce release stresses. Unfortunately, current design procedures overestimate the strength of the member at some sections and there have been instances in which failures under test or overload conditions have been observed. In this paper, a rational method for designing such members using strain compatibility is proposed and illustrated with examples. Code changes are also suggested.