The aim of this study is to provide experimental and non-linear numerical investigation of the mechanical connections with a pair of steel and concrete filler plates laminated to transfer axial loads and moments cross the column joints for precast concrete frames. The extended beam and column plates are, then, interconnected by high-strength bolts. The proposed connection for both steel-concrete composite precast frames and reinforced concrete precast frames under the condition of fully or partially restrained moment connections is to replace conventional monolithic cast-in-place concrete frames. The structural behavior based on the rate of strain increase of the novel mechanical beam-column joints with laminated metal and concrete plates including the extended endplates, rebar, and steel flanges was numerically investigated to understand the structural performance of the structural elements comprising the proposed mechanical joints for frames. The numerical structural performance considering concrete damaged plasticity was in good agreement with the test observations at concrete, rebar, and steel flanges in terms of strains, load-displacement relationship, and the influence of the endplates on the structural elements of the proposed joints; numerical data were calibrated to test data in microscopic level to numerically present the real-world behavior with strain evolution of the proposed beam joints.