An innovative analysis method is proposed in this paper for the determination of ultimate resistance of prestressed concrete beams. The proposed method can be applied to simply supported or continuous beams in a unified manner whether structure and external loads are symmetric or not. Through the iterative nonlinear strain compatibility solutions, this method can also be applied to the non-prismatic section/un-symmetrical composite structures under moving load. The conventional studies have used the failure criteria when the strain of concrete reaches 0.003. However compared with bonded case, the value of strain in the reinforcement is much smaller than bonded case, thus, unbonded prestressed cases show compressive failure mode. It is shown that the proposed method gives acceptable results within 5% error compared with the prior experimental results. It can be shown that the proposed method can reach the solution much faster than typical three-dimensional finite element analysis for the same problem. This method is applicable to the existing unbonded prestressed members where deterioration has occurred leading to the reduced ultimate resistance or safety. In all, the proposed procedure can be applied to the design and analysis of newly constructed structures, as well as the risk assessment of rehabilitated structures.

Abstract
 1. Introduction1
 2. Existing methods and proposedstudy
 3. Proposed model for evaluationof ultimate strain in unbondedtendons
 4. Procedure for calculation of theinteractive nonlinear section analysis
 5. Validation for unbonded PSCmembers
 6. Concluding remarks
 References

• 조태준(대진대학교 건설시스템공학과 부교수, Dept. of Civil Engineering, Daejin University) | Cho, Taejun
• 김명한(국립목포대학교 건축공학과 부교수, Dept. of Architectural Engineering, Mokpo National University) | Kim, Myeong-Han 교신저자