Estimation of seismic response in planar x-braced multi-storey steel frames

Abstract eng:
An extensive parametric study on the inelastic seismic response of X-braced steel buildings is presented. More than 150 regular multi-storey tension-compression X-braced steel frames are subjected to an ensemble of 30 ordinary (i.e., without near fault effects) ground motions. The records are scaled to different intensities in order to drive the structures to different levels of inelastic deformation. The statistical analysis of the created response databank indicates that the number of stories, period of vibration, column stiffness and distribution of strength along the height of the frame influence the response of X-braced frames. Strength deterioration in post-buckling region varies with the brace slenderness ratio, thus this parameter also strongly influences the amplitude of inelastic deformation. On the other hand, EC8 adopts a unique value of behaviour factor q for every X-braced structure. Stepwise regression analysis is employed in order to derive simple expressions which take into account the aforementioned influences and offer a direct estimation of the behaviour (or strength reduction) factor, the drift and the ductility demands. The proposed expressions are used for the seismic design of steel structures according to the performance-based seismic design methodology and the hybrid force/displacement method, which combines the advantages of the force-based and displacement-based seismic design methods. A comparison of the proposed method with the procedures adopted in current seismic design codes reveals the accuracy and efficiency of the former.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket