Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2022-2023)

When industrial, commercial and residential buildings are designed in Canada to resist seismic load, two structural frames are frequently used: steel multi-tiered braced frames and steel moment-resisting frames. Multi-tiered braced frames have two or more bracing panels stacked between the ground and roof levels. Moment-resisting frames are built from beams and columns that are rigidly framed together. Research on behaviour of both systems led to seismic design guidelines and adaptations in steel design standards. However, recent analytical and experimental studies observed several undesirable failures that are not fully understood. Further, some failures are not properly addressed in current steel design standards.

For multi-tiered braced frames under earthquake loads induced in the plane of the frame, special design requirements were recently proposed to improve frame behaviour. Still, frame stability may be compromised by concomitant out-of-plane bending moments induced in the frame columns; this must be reflected in design. Alternative design strategies that reflect actual behaviour of the frame under earthquake loads and reduce construction costs must also be developed for better stability response.

For moment-resisting frames under earthquake loads, flexural yielding and local buckling may cause instability of columns. By understanding combined effects, we can develop suitable earthquake-resistant design criteria that reflect interactions.

My long-term research program aims to develop novel systems and design methods that improve seismic response and safety of steel structures in Canada, with minimized construction costs. This research program’s general objective is to develop seismic design guidelines for steel multi-tiered braced frames and moment-resisting frames in order to prevent column instability.

The specific objectives of this research program are to:

1) develop design methods for columns of multi-tiered braced frames under coupled in-plane and out-of-plane seismic demands

2) develop special analysis and design methods to control in-plane seismic behaviour of multi-tiered braced frames by selection of bracing members

3) establish strength and stability requirements for dominant lateral stability limit states of deep, slender moment-resisting frame columns under seismic load effects.

Our methods for each objective include theoretical modeling, experiments and structural analysis knowledge. We will develop seismic design recommendations for the next Canadian steel design standard. Furthermore, we will provide practitioners with improved analysis and design tools that can be applied in day-to-day practice.