Investigation of Seismic Performance of Asymmetric Structures Using Rotational Friction Moments

Abstract

Design based on performance enables engineers the selection of a wide range of performance targets for design of buildings according to a suitable method that fulfills the selected objectives.

Due to the fact that frictional dampers play an important role in the energy depreciation and the decrease of the story drifts while buildings is affected by lateral forces, the use of dampers in the structures have been evaluated both technically and feasibility through initial studies and from references such as the information of researches, papers and relevant articles, and similar designs implemented with the damper.

In this research, the seismic performance of rotational frictional dampers in asymmetric frames is investigated, which is an irregularity caused by the cutoff of the lateral resistance system. Non-linear time history dynamic analyses were performed on 6, 9 and 12-story moment resistance frames with various spans of 4, 5 and 6 meter and irregular in height due to discontinuity in lateral resistance system. The frames have also been braced with inverted chevron type bracing equipped with frictional dampers. The frames were designed and loaded to comply with the requirements of Seismic Resistant of Building-Code of Practice (std 2800), fourth edition and Building National Regulations NO. 10, 1392 edition. The Sap2000 and Opensees software were used for this analysis.

The results showed that the use of this type of dampers in irregular steel structures increases energy absorption and improves the vibration behavior of the structure such as reduction of base shear, story drifts and internal forces.