Macromodel to evaluate ultimate strength and deflection for beam in unbonded precast prestressed concrete frame

A macro-model, which can reproduce the flexural behavior of the cruciform unbonded PCaPC subassemblage, and an evaluation method of the ultimate flexural strength and deflection of a beam are proposed based on a theoretical approach. In the macro-model, after an opening occurs at the connecting interface between a precast concrete column and a beam due to bending moment, the beam rotates as a rigid body. Beam axial deformation resulting from compressive strain, which develops at the extreme compression fiber along the entire length of the beam, is supposed to concentrate on the beam end. Predicted ultimate flexural strength and deflection of a beam by the proposed method showed a good agreement with the previous experimental results.