Effect of openings through sheath on shear behaviors of beam-column joint in post-tensioned precast frame

3-D finite element analyses were conducted on post-tensioned precast concrete frames to investigate the shear behaviors of beam-column joints having some openings through sheaths. The compressive damage and confining effect in the beam-column joints were numerically estimated based on the 3-D stress state. Analytical results indicated that the shear strength of the beam-column joint decreased considerably with increasing opening ratio without beams installed orthogonally. If, however, the orthogonal beams were installed, the shear strength of the beam-column joint increased by 20 % and the decrease in shear strength due to opening was softened because a high confining pressure was generated.