SHEAR STRENGTH ASSESSMENT OF EXISTING PRESTRESSED CONCRETE MEMBERS

Assessment of existing structures is becoming a more and more important part of structural engineering work. In lieu of special recalculation provisions, the assessment is generally based on current codes. These codes were developed in order to design new structures and contain explicit and implicit safety margins that might lead to an underestimation of actual member strength when applied to existing structures. This paper presents selected results from recalculations performed on prestressed concrete beams with straight and inclined tendons tested in shear in 1973. Several shear design approaches from current codes, including new Model Code 2010 methods, were compared. It was observed that the different approaches on the one hand tend to underestimate the actual member strength and on the other hand yield greatly varying results. The obvious need for further research in the field of shear assessment of existing prestressed concrete members is being specified.