VERIFICATION TESTS OF THE DYNAMIC BEHAVIOR OF THE NOVEL FRICTION-BASED ROTATIONAL DAMPER USING SHAKING TABLE

A friction damper is regarded as one of the most effective structural control devices in view of regulating the inertia force induced from the upper structures and effective energy dissipation. Despite a large number of friction dampers or bearings have been used for civil and architectural structures, those devices generally require large deformation and stable vertical load induced on the device in order to attain a desirable control performance. In order to overcome such difficulties, a new friction-based damper was developed. The new damper has several steel arms that are linked each other by a bolt in order for them to rotate freely, and carefully manufactured disk friction materials are embedded in that link. By connecting these arms to the upper and lower structures, horizontal deformation of the structure is converted into the rotational motion of the link and disk. The damper requires significantly less space for installation compared to the traditional friction dampers in order to attain the large friction energy dissipation. Moreover, the friction force is easily controlled by a torque of the fastening bolt, independent from the vertical load of the upper structure. In this research, dynamic performance of the proposed damper was studied through a large-scale shaking table tests on which the girder and bearings were mounted. It was confirmed through periodical loading tests that the damper generated the stable friction force regardless of the loading frequency. It was also found that the damper successfully introduced the supplemental damping to the structure under earthquake motions.