VIBRATION AND MODAL-ANALYSIS OF STEEL FRAMES WITH SEMIRIGID CONNECTIONS

In practical design, frames are assumed to be connected either by rigi d or pinned joints. Strictly speaking, all joints are semi-rigid, so t his assumption does not normally represent the actual behaviour of a r ealistic steel frame. Due to extensive research into the behaviour of frames with semi-rigid connections and the availability of low-priced personal computers, the idealized pinned or rigid joint assumption for the simplified analysis of a steel structure may not be necessary or justifiable. So far, most research on the subject has concentrated on the static linear and nonlinear analysis of flexibly jointed steel fra mes. The dynamic behaviour of steel structures with semi-rigid joints has not been extensively investigated. The response of a steel frame w ill be of interest to the designer for the purpose of ensuring the saf ety and serviceability of the structure under the action of dynamic lo ads. This paper is addressed to the extension of the well known stiffn ess matrix method of analysis for framed structures to cover a more ge neral case of vibration and stability analysis of flexibly connected s teel frames.