Hospitals play a key role in the healthcare system, especially during the emergency response to seismic disasters. Experiences from past earthquakes have clearly showed the importance they have in reducing the number of fatalities by providing adequate assistance to injured persons. Unfortunately, past events have also demonstrated that hospitals may be particularly vulnerable to earthquakes due to their high susceptibility to non-structural damage. Loss of functionality in a hospital may be experienced, in fact, even in the case of minor structural damage because of utility service interruptions, dislodgment of medical equipment, and overturning of cabinets for chemical or hazardous materials. The objective of this project is to develop analysis tools for the seismic assessment of hospitals that allow estimation of the functionality loss caused by non-structural damage. In particular, the research aims to: (1) identify those non-structural components that are vulnerable to earthquakes and critical for the functionality of the hospitals; (2) develop models for predicting the seismic capacity of these components; (3) proposing new equations for their seismic demand estimation; (4) define a performance measure to estimate functionality loss as a consequence of non-structural damage; (5) analyze a case study consisting in a real hospital building of Sapienza. The products of the research will be finally used to produce a guideline for assessing the seismic risk of functionality loss. The general motivation for this research stems from the belief that, especially in areas of low-to-moderate seismicity, a better response of hospitals to earthquakes can be achieved at a relatively low cost if the risk of non-structural damage is reduced. It is evident that in order to pursue this goal reliable analysis tools for predicting the effects of non-structural damage, which unfortunately are still lacking, are required.
The currently available analysis tools for predicting the loss of functionality in hospitals caused by non-structural damage have shortcomings as to their levels of accuracy. The aim of the project is to contribute to the current state of the art of research in this field as follows.
1) By investigating, through an experimental campaign, laboratory and medical equipment whose seismic capacity is still unknown [1];
2) By proposing new models for predicting the seismic capacity of NSC and systems usually adopted for their seismic protection [2]; few are currently available for a limited number of components, and these are all characterized by large uncertainties [3-4];
3) By developing new equations for estimating the earthquake-induced acceleration demand in non-structural components, as expressed in terms of uniform hazard floor response spectra; in the literature, proper solutions still lack to account for the possible non-linear behavior of the supporting structure and the component, the structure-component dynamic interaction, and the ground motion vertical component (e.g. see [5]).
4) By developing new equations for predicting correlation between the acceleration and the deformation demand in NSC; studies on this topic have already been carried out (e.g. [6]), but no predictive equations have been proposed;
5) By identifying the performance parameter that best quantify the loss of functionality in hospitals; parameters have already been proposed (e.g. see [7]) but a general consensus still lacks.
6) Finally, by integrating the developed tools into the PEER framework for probabilistic seismic loss assessment, widely used in Performance-Based Earthquake Engineering but mainly for estimating economic loss and structural collapse.
The findings of the research will certainly contribute also in studies dealing with the risk of facilities other than hospitals, having critical functions connected with the seismic performance of NSC, such as data centers, industrial plants that process hazardous materials, and museums with fragile collections.
The results of the research are likely to be implemented in Seismic Design and Assessment Methodologies for the Next Generation of Non-structural Building Code Provisions. The principal investigator of the proposal, Andrea Lucchini, is in fact member of a working group established by the Italian National Research Council (CNR) to draft guidelines on "Non-Structural Safety". Anna Maria Giovenale is a member of the Italian High Council of Public Works, advisory body of the Ministry of Infrastructures and Transport in charge of developing safety standards for the design of buildings and structures. Paolo Franchin is part of the Project Team for the revision of the European seismic code "Eurocode 8 Part 3 - Assessment and retrofitting of buildings".
References
[1] Cosenza E, Di Sarno L, Maddaloni G, Magliulo G, Petrone C, Prota A. Shake table tests for the seismic fragility evaluation of hospital rooms, Earthquake Engineering and Structural Dynamics, Volume 44, Issue 1, 2015.
[2] Fathali S, Filiatrault A. Experimental Seismic Performance Evaluation of Isolation/Restraint Systems for Mechanical Equipment, MCEER-07-0007 & MCEER-07-0022, 2007.
[3] Grigoriu M, Waisman F. Seismic reliability and performance of non-structural components. Proceedings of seminar on seismic design, retrofit and performance of nonstructural components, ATC 29-1, Applied Technology Council, Redwood City, CA, 1998.
[4] Shinozuka M. Seismic risk assessment of non-structural components in hospitals, FEMA/USC Hospital Report No. 4, University of Southern California, Los Angeles, 2001.
[5] Lucchini A, Mollaioli F, Bazzurro P. Floor Response Spectra for Bare and Infilled Reinforced Concrete Frames, Journal of Earthquake Engineering, Volume 18, Issue 7, 2014.
[6] Lucchini A, Franchin P, Mollaioli F. Probabilistic seismic demand model for nonstructural components, Earthquake Engineering and Structural Dynamics, Volume 45, Issue 4, 2016.
[7] Cimellaro GP, Reinhorn AM, Bruneau M. Seismic resilience of a hospital system. Structure and Infrastructure Engineering, Vol. 6, Nos. 1-2, February-April 2010, 127-144.