The authors are working to develop a construction method that incorporates semi-rigid timber beams into a steel frame structure to form a rigid frame structure. In structures constructed by this method, the joints of the semirigid timber beams, consisting of drift pins inserted into steel plates, resist seismic moments, generating a bending yield at the root end of the inserted U-shaped steel plates. We believe this explains the specified bearing strength and deformability achieved. We performed experiments and analysis to verify the structural performance of structures incorporating CLT semi-rigid beams. This paper describes the results of full-size in-plane bending tests performed on semi-rigid beam joints; tensile tests performed on individual drift pin joints; and the finite element method analysis used to assess the experimental results.