CALCULATION OF FORCE TRANSMISSION RATIO OF FRICTION HIGH STRENGTH BOLTS CONNECTIONS

High strength bolted friction grip (HSFG) joints are widely used in steel bridges, in order to study the force transmission ratio of HSFG joint, the load-displacement curve of a single bolt was fitted and the mechanical model of long HSFG joint was constructed, based on the reference’s experimental results and finite element analysis. By the grounds of deformation coordination conditions, a theoretical calculation method for the force transmission ratio of each row bolt is proposed through solving the static equilibrium equations. To verify the correctness of the theoretical method, two bolt joints were designed and the force transmission ratio was measured. Experimental results show that the proposed method is in a good agreement with the theoretical results. In the last, parametric analysis is conducted, and the analysis results show that: the force transmission ratio is significantly related to the thickness ratio of the core plate to the cover plate, to the number of bolt rows, to the spacing of bolt hole, and the like. When the number of bolt rows is greater than 5, the force transfer ratio of the first row of bolts is suggested to be 0.389.