1.2 Seismic Response of Non-Structural Components
Building Seismic Ceiling Fragility using Spectral Acceleration
J. Singh, G.A. MacRae, R.P. Dhakal & S. Pampanin
ABSTRACT: Seismic damage to ceilings can cause significant downtime and economic loss in addition to life safety risk. In order to understand this risk and develop mitigation strategies a small project on non-structural damage was recently funded by the FRST Natural Hazards Platform at the University of Canterbury. This project looks at the demands imposed on ceilings in a seismic event. The engineering demand parameter of interest is the total peak floor acceleration. Two different ceiling types are investigated; the “perimeter fixed” and the “floating type” ceiling. Firstly ceilings are modelled explicitly with its own mass in a single storey one bay frame to evaluate the changes in response relative to the ceiling above for a number of parameters. Secondly, median peak total floor accelerations for the 10 storey Redbook building are obtained by conducting time history analysis with a suite of 20 ground motion records. Thirdly, this information is combined with ceiling system fragility information based on floor acceleration to obtain the system fragility information based on ground motion parameters.
Ceiling Fragility of Japanese Ceiling Systems
Y. Sato, S. Motoyui, G.A. MacRae & R.P. Dhakal
ABSTRACT: In Japan, the performance of modern seismically designed building structures has been good. However, non-structural damage is still significant and several people were injured by the collapse of ceiling boards in a 2005 earthquake. Ceiling failure can cause significant downtime and economic loss in addition to life safety risk. Previous studies have shown that the behaviour of Japanese ceilings can be accurately modelled. In this paper, the fragility of a typical Japanese ceiling system is obtained through Monte-Carlo analysis using 2D finite element analysis and the statistical variation of the strength of connections from experimental testing. This information is used to estimate both ceiling damage and loss to overall building structures.
Seismic Retrofit and Shaking Table Test of Medical Equipment in a Hospital
J-F. Chai & F-R. Lin
ABSTRACT: Due to the variety in the categorization of nonstructural components and medical equipment in a hospital, before embarking on seismic design, the critical and/or vulnerable nonstructural items should be identified and prioritized. In this study, consulting with the constructors and hospital facility managers, the procedures and accompanied tools including the screening criteria, simplified seismic evaluation form, design requirements and appropriate seismic restraints are proposed and recommended for the nonstructural components and equipment in a hospital. Furthermore, some critical and vulnerable medical equipment items were chosen for shaking table tests to verify the application of proposed simplified evaluation forms and recommended seismic restraints. Based on the modeled specimens of medical equipment, the test results revealed that restraint devices actually contribute to decrease displacement response, but it increases acceleration response of the equipment due to the impact effect. Besides, damages of adhesive layer between restraint devices and equipment or anchors at partition wall appeared under larger earthquakes. Based on the test results, the simplified evaluation form and seismic restraints were modified to be applicable for free-standing medical equipment, and further, the pull-out strength of partition wall and the adhesive strength of non-destructive devices were taken for the next research subjects for seismic design of medical equipment.
Design Recommendations for the Improvement of the Seismic Performance of Steel Storage Racks
Barry J. Davidson & Anthony P. McBride
ABSTRACT: The use of steel storage racks has become more common in retail situations where their failure during an earthquake could give rise to “life safety” issues. The paper describes the differences between storage racks and more regular building frames and how these differences are expected to alter their seismic performance. The current seismic design criteria for storage racks are compared with that for building frames and it is concluded that these frames are typically designed to a much lower strength than what would be required of standard structures.
A Revised Guide for the Design, Construction and Operation of High Level Storage Racking Systems following the Experience of the Darfield Earthquake
G J Beattie & S R Uma
ABSTRACT: In 2006, BRANZ and the University of Canterbury produced Design Recommendations for the Seismic Design of High Level Storage Racking Systems with Public Access as a Design Guide. The Guide is particularly applicable to supermarkets, home handyman stores and bulk retail outlet stores and was made available to the known racking system manufacturers and importers in NZ. During the Darfield earthquake, it appeared that racking systems in these operations generally behaved satisfactorily. However, there were anecdotal reports that several industrial storage racking systems had failed resulting in multi-million dollar losses from damaged product stored on these systems, with the racking systems themselves needing to be completely replaced.
This paper describes an investigation of both the behaviour of systems that reportedly performed well and the failure mechanisms of those that did not. Various racking manufacturers and retail owners were consulted to establish the pre-event condition and loading of the systems and the response of the systems in both ‘public accessible’ and ‘industrial’ situations. Investigations by the authors highlighted an apparent lack of consistent national control over the design and construction of racking systems. Progress towards the publication of a revised and extended Guide is also described.