Development of an amplified added stiffening and damping system for wood-frame shear walls

Abstract

The effectiveness of seismic dampers to improve the lateral performance of timber structures may be heavily diminished if restrictive lateral drift limits as set by building codes, governs the design of the structure. This paper presents an innovative approach to improve the performance of seismic dampers installed in stiff wood-frame shear walls. U-Shape Flexural Plate dampers with a novel internal restraint system, were installed in a 4880x2475 mm wood-frame shear wall with an Eccentric Lever-Arm System which aimed at amplifying the displacements by transferring them from the shear wall to the dampers. Cyclic tests were conducted to four specimens. Initial test results showed that the presented amplifying system suffered concentrated losses of stiffness at some connections joints reducing its real efficiency. The loss of displacement transmission to dampers was retrofitted, and the results showed a great benefit in terms of resilience for the damped shear wall in contrast with unprotected ones. It was found that this approach provides a feasible solution to enhance the lateral performance of wood-frame structures.