Control of structures can be done by adding suitable control devices such as actively controlled
actuators, strengthening and stiffening elements, and/or adding passive damping devices. The control
demands often require reducing however the induced forces in structures and eliminating essential
structural elements and masses that contribute to generating inertial forces during earthquakes.
Recently the speaker and his colleagues developed design and implementation concepts which weaken
the structural system reducing the induced forces at the expense of increased deformations, while
correcting and controlling such increases with supplemental damping. This results in an improved
behavior, in particular when applied to existing structures, as well as introduced in the new
construction. The concept and implementation was studied by the author's team theoretically using
control methods and experimentally using structural models with weakening, or softening, devices and
simulated earthquakes. The implementation of such concept requires particular attention and balance of
safety and stability.
The presentation will introduce the concept, the development of weakening components (such as rocking columns), the innovation of true negative stiffness devices, the theoretical and experimental verification of the concept using simulated earthquakes in the laboratory, and the development of design procedures using active control theories.
Andrei M. Reinhorn is a retired professor (emeritus) at University at Buffalo and was involved in
education, research and consulting in structural dynamics with applications to earthquake engineering,
wind effects and extreme loads engineering. He is a graduate of the Technion - Israel Institute of
Technology (BS 1968, PhD 1978) followed by an academic career at University at Buffalo - State University
of New York - for over thirty years. Prof Reinhorn conducted research in evaluation and
design of building structures experiencing inelastic
deformations near collapse. He also developed modeling and solution techniques for structural control
and base-isolated structures. Computational platforms 3D-BASIS and IDARC developed by him and his
coworkers are widely used by academics and design professionals around the world. He pioneered
experimental structural control that brought the experimentation from small scale laboratory
implementations to the full scale real-life realization of controlled structures using active tendon
systems in Japan. He was one of the pioneers in defining the disaster resilience of communities and
its quantification, using basic principles of process control. Most recently he developed new
approaches to analysis of structures using State Space Approach (SSA) and Mixed Lagrangian Formulation
(MLF). He developed integrated computing and experimentation methods, which are in the forefront of
hybrid simulation techniques. As one of its designers and founders, he directed one of the largest
laboratories in the US for structural engineering and earthquake simulations (SEESL) located at
University at Buffalo.
Professor Reinhorn was awarded the 2011 ASCE-Nathan M. Newmark Medal. He has received numerous other awards including 2007 SUNY Chancellor's Award for Excellence in Scholarship and Creative Activity, 2006 UB - University at Buffalo "Exceptional Scholar" Sustained Achievement Award, 2005 ASCE/CERF Charles Pankow Award for Innovation, and 1998 AGC-Build San Diego Award., for work related to applications of structural control. More information can be found at Prof. Reinhorn's website
Friday, April 5th, 2013
12:00 pm EST
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