ABSTRACT

The target of this present MSc thesis is to perform a parametric study on a novel hybrid

steel frame, in order to obtain all the qualitative parameters that define its inelastic

response under earthquake excitation. The frame is a combination of a concentrically

braced frame system with a moment resisting frame system. The CBF-MRF frame

illustrates two novel characteristics, a brace to beam-column joint connection using web

hourglass pins and fuse elements on the beams to dissipate energy. For this purpose, the

frame is subjected to Incremental Dynamic Analysis, for a set of 44 far-field ground

motions. The record set selection and scaling was according to the provisions of ATC63

FEMA P-695. The dynamic analyses were conducted using the OpenSEES software

framework. In order to assess the performance of the frame accurately, low cycle

fatigue effect was taken into account in the WHP connections. The current study of the

proposed frame has been based on previous experimental results and finite element

computer models. Statistical tools have been used to minimise the error margin and

make accurate predictions for the behaviour of the different elements of the frame. The

aim is to investigate the collapse capacity of the proposed frame. In this cause, peak and

residual storey drifts have been inspected with respect to the local and global ductility

levels. Therefore, a performance based engineering approach has been implemented in

this study, defining the performance level of the current configuration. Furthermore, the

collapse mechanisms of the frame are being investigated, so as to confirm the validity of

yield and fracture predictions of both the WHP connections and the beam fuses. Finally

the frame is examined for collapse evaluation according to the procedures described by

FEMA P-695 guidelines. The analyses results were afterwards used for the vulnerability

assessment of the frame and the extraction of the fragility curve.