Development of a novel friction-based structural connection with predetermined discrete variable friction forces at target design displacement levels

This research presents a simple and practical structural connection able to develop predetermined discrete variable friction forces at target design displacement levels. The innovative connection is termed Modified Friction Device (Modified FD). Modified FDs are used to transfer the seismic induced horizontal forces from the floors to the core wall seismic force-resisting system of a building. The schematics of the physical embodiment of the Modified FD are presented. The components and the assembly of the Modified FD are discussed. The mechanics of the Modified FD are explained. Results from static structural analyses of two types of finite element models of the Modified FD are presented. The first model is developed using solid finite elements and it is used to assess the expected kinematics and the expected force-displacement response of the Modified FD. The second model is developed using a truss finite element and it can be used to efficiently simulate the force-displacement response of the Modified FD in numerical earthquake simulations of structural systems. 

Schematic representation of the Modified FD (a) components, (b) exploded view, (c) assembly, and (d) front view with initial gap dimensions D1 and D2 between the bearing plates and the slots in the external plates.

Expected kinematics and force-displacement response of the Modified FD 

Modeling approaches of the Modified FD presented in Chen et al. (2023): (a) Solid Model (b) Truss Model