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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.

The seismic performance of a corner beam-column joint in reinforced concrete frames was studied by testing two three-dimensional corner beam-column subassemblage specimens without slabs under constant column axial load and bi-directional lateral cyclic load reversals. The column-to-beam flexural strength ratio was varied from 1.4 to 2.3 by changing the magnitude of column axial load. Although a sufficient margin to prevent shear failure was provided to a corner beam-column joint in the test, the subassemblage specimens failed in joint hinging after beam and column longitudinal bars and joint hoops yielded. The ultimate joint hinging capacity of a corner joint under bi-directional lateral loading was enhanced by an increase in column compressive axial load, and can be estimated based on the new mechanism proposed by Kusuhara and Shiohara.

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Wall-type precast reinforced concrete (WPC) residential buildings were widely constructed in Japan since the middle of the 1960s. A large number of these types of buildings still exit, and maintain high structural quality; however, their residential units are rather small and are extremely standardized, which do not suit modern living use. In order to create new openings in existing WPC walls to widen possibilities for plan changes during renovations, the authors conducted experiments of half-scale WPC shear walls with new openings and reinforcement. In addition, inelastic static pushover analysis models were created, that can reasonably simulate the shear wall behavior. In this paper, the analytical models are developed for full-scale, standard WPC residential buildings to evaluate the collapse mechanism and ultimate lateral strength. Through the static pushover analyses, the ultimate seismic strength (base-shear) coefficient is determined to be approximately 0.6 and rocking of the shear walls accompanied with failure of the connecting reinforcement at the first floor is the primary mechanism. Furthermore, in some analysis models with new openings in the shear walls, the influence on the ultimate lateral strength and failure mechanism is limited.