Abstract: The sources of deformation for a fiber-reinforced concrete (FRC) beam-column-slab subassembly are considered to be contributed by the joint shear deformation, beam deformation and column deformation. The Bayesian parameter estimation was applied to predict the joint shear capacity. Mechanical analysis was conducted to establish the moment-curvature model of the beam end and column end. A complete model applicable to the subassemblies is proposed. The computational results show that when the column-to-beam strength ratio increased from 1.1 to 1.6, the contribution of the joint shear deformation to total displacement at peak load is decreased by 37.4%, and the contribution of beam deformation is increased by 58.8%. The slab was beneficial to control the joint shear deformation. The subassemblies with slabs of flange width of eight times the slab thickness on each side of the beam could control the joint shear deformation more effectively. The contribution of the joint shear deformation to total displacement at peak load can be decreased by 33.4%, and the contribution of the beam deformation increased by 42.9%.