MSc Dissertation Abstract
- 1. 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.