Theme Lecture – Performance-based design of steel structures for enhanced lifecycle seismic performance
D. Lignos, Associated Professor, Department of Civil Engineering and Applied Mechanics, École Polytechnique Fédérale de Lausanne (EPFL), France
Buildings designed in seismic regions exhibit structural and nonstructural losses due to repairs and downtime following earthquakes. With regard to steel moment resisting frames (MRFs), which form a widely used lateral load resisting system in steel frame buildings, these losses may be attributed to nonlinear geometric instabilities of steel beam-column members. These usually lead to residual member shortening in addition to residual drifts. As such, the risk of building demolition may be high after extreme earthquake events. In this presentation we introduce, by means of large-scale experimentation and high-fidelity nonlinear building simulations, novel concepts that (a) retain the simplicity in the design process of steel MRFs; and (b) limit structural damage in their anticipated dissipative zones, thereby minimizing lifecycle costs over a building’s life expectancy. Probabilistic tools to facilitate the performance-based design of steel frame buildings for enhanced seismic performance are introduced.