Simplified Method for Serviceability Design of Cracked Prestressed Concrete Members Belonging to Class C Section

In current ACI 318 code, crack control design criterion for prestressed concrete (PSC) members is stricter than conventional reinforced concrete (RC) members. In particular, it is stipulated that the net tensile stress of prestressing strands should be controlled under 250 MPa (36.3 ksi) in the serviceability design of PSC members belonging to the Class C section that is expected to be cracked under service load conditions. To this end, the nonlinear cracked section analysis is essentially required to estimate the tensile stress of the prestressing strands under the service loads, which requires cumbersome iterative calculations in practice. This study aims to propose a simplified method to estimate the net tensile stress of the prestressing strands (Δfps) under the service load conditions and also a tabulated checking method whether the net tensile stress (Δfps) exceeds the stress limit with respect to the magnitude of effective prestress (Δfse). Finally, applicability of 2,400 MPa (348 ksi) Grade strands is also experimentally investigated.