Conference on Earthquake & Civil Engineering Dynamics (SECED 2019)
Abstract
In the last two decades many researchers focused on the development of innovative
building structures with the aim of achieving seismic resilience. Among others, steel Moment
Resisting Frames (MRFs) equipped with friction devices in beam-to-column joints have emerged
as an effective solution able to dissipate the seismic input energy while also ensuring the damagefree behaviour of the system. However, to date, little attention has been paid to their column
bases, which represent fundamental components in order to achieve resilience. In fact, column
bases designed by current conventional approaches lead to significant seismic damage and
residual drifts leading to difficult-to-repair structures. This work assesses the seismic performance
of steel MRFs equipped with an innovative damage-free, self-centering, rocking column base
joints, developed in accordance with the aims of the European project FREEDAM. The proposed
column base consists of a rocking splice joint where the seismic behaviour is controlled by a
combination of friction devices, providing energy dissipation capacity, and pre-loaded threaded
bars with disk springs, introducing restoring forces in the joint. The design procedure of the
column base is presented, a numerical OpenSees model is developed to simulate the seismic
response of a perimeter seismic-resistant frame, including the hysteretic behaviour of the
connection. Non-linear dynamic analyses have been carried out to investigate the effectiveness
of the column base in protecting the first storey columns from yielding and reducing the residual
storey drifts. The results show that the damage-free behaviour of the column bases is a key
requirement when self-centering of MRFs is a design objective
