Effects of shear rate on cyclic behavior of dry stack masonry joint

- Novel dynamic friction test concept is supposed and verified by finite element model.
- Effects of shear rate on cyclic behavior of dry bricks (DB) are studied experimentally.
- A dynamic friction characteristic model with 5 stages of the DB joint is addressed.
- A formula of calculating the dynamic friction coefficient of DB is proposed.
- Stribeck effect is considered in calculating the dynamic friction coefficient of DB.

Dry stack masonry (DSM) constructed without mortar has been suggested for use in reinforced concrete (RC) frame structures. DSM can considerably improve the seismic performance of masonry infill panels and frames. For this type of structure, the characteristics of frictional forces between the bricks are crucial for energy dissipation, but few researchers have studied these forces. In this paper, a novel dynamic loading test concept is proposed. The dynamic friction characteristics of dry bricks were investigated using this concept. A numerical comparison between the novel test and a triplet test was conducted to validate the advantages and stability of the novel test concept. Nine different loading speed tests based on the novel test concept were conducted to study the effects of shear rate on the cyclic behavior of mortarless masonry joints. Investigating dynamic friction hysteretic curves yielded a dynamic friction characteristic model of dry brick joints, comprising five stages: presliding, softening transition, macroslip, hardening transition, and unloading stages. A formula regarding the Stribeck effect on the macroslip stage is proposed to calculate the dynamic friction coefficient, which is of noteworthy importance for use in day-to-day research on the dynamic friction characteristics of dry bricks.