A future for earthquake resilient design: using advances in applied nonlinear dynamics Seminar
- Time:
- 16:00
- Date:
- 8 May 2018
- Venue:
- Highfield Campus, 13/3017
Event details
In earthquake engineering, the current state-of-practice is to utilise nonlinear behaviour in the form of inelasticity.
Abstract
The nonlinear dynamics of carefully designed inelastic systems (i) limit the total force transferred to the structure from the ground and (ii) increase the energy dissipation within the structural system: both are potentially beneficial. Given that the magnitude of the earthquake ground motion, and more specifically the ground motion time series, is generally unknowable a priori this approach was insightful and pragmatic in the 1970s. However, the consequences of permitting inelastic behaviour are obvious: it results in damaged structures (which have hopefully not collapsed) after the earthquake. These damaged structures can be very costly to repair/rebuild.
The theme of this lecture is to consider a range of alternative approaches that make use of non-linear elastic, possibly non-smooth behaviour, such as structures with opening and closing joints, rocking systems, slip-stick frictional behaviour and nonlinear tuned mass dampers. Much of the nonlinear dynamics of such systems find a more natural home in mechanical engineering, physics and applied mathematics. The aim is to identify beneficial behaviour that mitigates our uncertainty in the loading time series without generating significant post-earthquake repair/rebuild costs. This requires us to go beyond our “black-box” FEA simulations and deepen our understanding of the complexity of nonlinear dynamics phenomena.
Speaker information
Nicholas Alexander , University of Bristol. Dr Nicholas A Alexander is a Senior Lecturer in Structural Engineering at the University of Bristol. His main research areas are Earthquake Engineering, Structural dynamics, Seismology and Nonlinear Dynamics. He is a member of the Institute of Mathematics, a Chartered Mathematician (UK) and a Chartered Scientist (UK). He has supervised, to date, 20 PhD students. He has written 53 international peer-reviewed journal papers, 70 international conferences papers and 2 undergraduate textbooks. He has an h-index of 15 in Scopus. His paper on the dynamics of a nonlinear tuned mass dampers was listed in the most cited papers in Journal of Sound & Vibration (2007-11). His paper on offshore wind turbine soil-structure interaction was listed in the most cited papers in Soil-Dynamics and Earthquake Engineering (2011-15). His paper on the nonlinear stress-strain behaviour of corrosion-damaged reinforcing bars was listed in the most Cited Engineering Structures Articles (2012-2016) He is a Co-I of the "SAFER: Seismic Safety and Resilience of Schools in Nepal" EPSRC grant £1.6m (2017-2019). He is a Co-I of an EU Horizon 2020 grant €1m, (2016-2018) and the PI of the EPSRC Global Challenge Institutional Sponsorship grant (2016) "A low-cost, sustainable technology for earthquake-resilient urban infrastructure in DC". He was Co-I on ESPRC: grant EP/D035562/1, “Workshop: Info-gap analysis of engineering systems: Robust decisions under severe uncertainty” (2006).