An Elasto-Plastic Model for Drift-Pin Joints Using Hankinson’s Yield Function and Its Application to Timber Grid Shells

This study presents an elasto-plastic analysis method for drift-pin joints. A nonlinear analysis program was developed using the Hankinson formula as the yield function to evaluate the combined effects of axial force and bending moment on drift-pin joints. The joints were modeled by beam elements connected through multiple drift pins whose elastoplastic behavior was described by a plastic flow rule. Numerical analyses were conducted for elliptic paraboloid grid shells with different drift-pin arrangements. The results showed that increasing the spacing of drift pins improved the bending resistance of the joints and increased shell buckling loads by approximately 10-20%.