Validating the sliding mechanics of office-type furniture using shake-table experiments

Trevor Z Yeow,Gregory A Macrae,Rajesh P Dhakal,Brendon A Bradley

doi:10.5459/bnzsee.51.1.1-11

Trevor Z Yeow, Gregory A Macrae + Show 2 more

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https://doi.org/10.5459/bnzsee.51.1.1-11

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Abstract

Pull-tests and shake-table tests of office-type furniture on carpet and vinyl flooring were performed to obtain friction coefficients, and validate the mechanics of content sliding and current modelling approaches. The static friction coefficient, μs, for furniture with and without wheels was between 0.13-0.30 and 0.36-0.45 on carpet flooring, respectively, and 0.07-0.13 and 0.39-0.45 on vinyl flooring, respectively. The kinetic friction coefficient, μk, was similar to μs for carpet flooring, but was up to 38% lower for vinyl flooring. Shake-table tests using sinusoidal floor excitations showed that: (i) the sliding force hysteresis loop was elasto-plastic on average, and (ii) peak total floor velocity significantly affected the extent of sliding. While it was found that the maximum sliding displacement obtained by numerical integration methods differed by a factor between 0.3 and 3.0 on a case-by-case basis, the average error was just 5%. Preliminary sliding analyses of furniture resting on single-degree-of-freedom structures of varying stiffness using a suite of ground motion records were performed. It was found that (i) the extent of sliding was not necessarily more severe in stiffer buildings despite the greater peak total floor acceleration demands, and (ii) considering only μk in content sliding analyses still produced reasonably accurate predictions.

Highlights

Building contents, such as hospital equipment or furniture, have the potential to slide over large distances as observed from past seismic events [1] and experimental shake-table studies [2,3]; potentially resulting in injuries, damage, and business/operational disruptions [2,4]
Numerical approaches follows Amonton’s and Coulomb’s dry friction laws [14], which state that (i) friction force is independent of the contact area, (ii) friction force is proportional to the normal force, and (iii) kinetic friction is independent of sliding velocity
To explain the limitations of considering AFT alone, the generic content and floor total acceleration and total velocity curves in Figures 10a and 10b, respectively, are examined. These curves were based on a single sinusoidal floor response cycle similar to that from Figure 7; where, ωT is the total floor response frequency, and T0 and Te are the times at which content sliding initiates and ends, respectively

Summary

Introduction

Building contents, such as hospital equipment or furniture, have the potential to slide over large distances as observed from past seismic events [1] and experimental shake-table studies [2,3]; potentially resulting in injuries, damage, and business/operational disruptions [2,4]. The average μk from both kinetic pull-tests versus sliding displacement relationship is shown in Figure 4 for contents on carpet flooring.

Results

Conclusion