The post doctoral offer is extended by Ministry of Italian University and Research (MIUR) under India- Italy Exchange Program for a period of two years with effect from 15th May 2007. The fellowship is assigned with a directive to work with Prof. Giorgio Serino, Professor, Dept of Structural Engg, University of Naples Federico II, Naples, Italy. The broad area of work is focusing the nonlinear analysis of different types of buildings subjected to seismic loading including developing technologies for seismic isolation and control of structures and infrastructures.
Technologies developed in the past for control of structural vibrations under seismic loading allow structures to achieve higher safety levels than conventional structures, even when designed using modern seismic guidelines. The enforcement of Ordinanza 3274 in Italy has two chapters exclusively on seismic isolation of buildings and bridges represented a turning point as a result of which most of new buildings are being designed with seismic isolation. The main objective of the fellowship work is to improve the knowledge of some specific aspects of design and functioning of passive and semi-active systems for seismic control of structures. Four main aspects of control techniques namely: 1) seismic isolation; 2) passive energy dissipation; 3) tuned mass; as well as 4) semi active control are being studied, out of which I am assigned to work on namely: 1) passive control of buildings- experimental and analytical studies for the validation and improvement of structural design, analysis and verification methods and of the device testing procedures; ii) Design methods of buildings with viscous devices and of light structures; as well as iii) seismic isolation of historical and monumental buildings. The activities include theoretical and experimental studies including parametric investigations and single case study analysis to set up design and verification methods of systems and devices of control algorithms. An extensive experimental program is chalked on large shake tables to perform proto type testing on the models. Due to high level of protection provided by the control systems, most of the tests are intended to be carried out under seismic actions without damage to the structure, thus giving an opportunity to learn important aspects on the device and structure behavior.
Experimental investigations on the damping devices for seismic isolation, energy dissipation and semi-active control are intended to be carried out i) to characterize the energy dissipating device, of different types namely a) magneto-rheological dampers, b) viscous dampers etc, ii) to verify the actual behavior of the devices under different working conditions, iii) to improve general design guidelines and verification rules and iv) to improve the modalities of experimental verification procedures as given in Italian and International norms.
The fellowship provided an opportunity to deliver finally the following: 1) guidelines and manuals with design calculations of energy dissipating devices namely a) hysteretic, fluid-viscous, visco-elastic, re-centering with or without viscous dissipation; 2) design manual with examples of application of dissipating devices for light weight structures; 3) guidelines and design indications which integrate and improve the current norm, for the seismic upgrading of historical-monumental buildings thorough seismic isolation; 4) proposal of norms for buildings with energy dissipation systems; as well as 5) proposal for modifications of seismic isolation norms for some aspects related to the simplified analyses of buildings which are some of them currently under the direct study of Prof. Giorgio Serino.
A detailed analytical investigation of a Sanctuary building in seismic zone II of Italian code was also carried out for its post-isolated behavior using response history analysis. The analytical results are compared with that of the actual seismic observations being made by the Italian National Seismic Observatory at Rome. Based on the comparisons, design alterations were suggested to the existing seismic isolation system installed in the Sanctuary recently. Also rehabilitation of the structural health monitoring of the Sanctuary building was studied and modifications/improvements on the existing structural health monitoring system was proposed. The structure was also accepted among the structures of the Italian Observatory of Structures (OSS), which represented a network of the National Seismic Service (SSN) of the Italian Dept. of Civil Protection (DPC), dealing with a set of public constructions in use in Italian seismic areas, that are instrumented with a local permanent monitoring system. Also, characterization of magneto-rheological dampers (designed by Moyer and Sony, Germany) and viscous dampers (designed by FIP Industriale, Italy) are carried out at the Structural Engg Lab of the Dept. Scaled model tests on buildings with these dampers were carried out.
In addition, teaching assistance was extended in developing a newly proposed e-learning course namely “Tecniche delle construzioni 2” dealing a part of advanced structural analysis (Matrix methods). The curriculum development had an active part in the regular teaching for under-graduate program in Civil Engg. (for the courses taught in English) and Graduate Program in “Emerging Technologies in Construction- ETeC) jointly done by University of Naples Federico II, Italy and University of Missouri Roula, USA.
Professor, Dept of Ocean Engg, IIT Madras: 18-07-2014 till date