SAFETYLIT WEEKLY UPDATE

We compile citations and summaries of about 400 new articles every week.
RSS Feed

HELP: Tutorials | FAQ
CONTACT US: Contact info

Search Results

Journal Article

Citation

Jäniskangas T, Pylkkänen KPK, Kolisoja P. Inj. Prev. 2018; 24(3): 224-231.

Affiliation

Department of Civil Engineering, Earth and Foundation Structures, Faculty of Business and Built Environment, Tampere University of Technology, Tampere, Finland.

Copyright

(Copyright © 2018, BMJ Publishing Group)

DOI

10.1136/injuryprev-2017-042335

PMID

28754662

Abstract

OBJECTIVES: To assess the influence of grain size distribution and moisture condition on aggregates' performance as an impact attenuation layer beneath playground equipment. SETTING AND METHODS: Impact attenuation of sands and gravels was tested using a guided headform with a uniaxial accelerometer inside. The result for impact attenuation was the acceleration value of the headform measured from four different drop heights and the Head Injury Criterion (HIC) calculated from it. The acceptable HIC value of a shock-absorbing layer is <1000, that is, less than the critical fall height. Tests were conducted with both dry and wet materials.

RESULTS: The impact attenuation of a shock-absorbing layer made of loose aggregate is determined mainly by the following material factors: maximum grain size, median grain size, uniformity coefficient, fines content, grain shape and moisture content. In addition, the moisture content of aggregate, especially sands, has a major impact on its impact attenuation capacity. Of the studied sands, coarse and gravelly ones had the best impact attenuation properties. Most of the examined sands were uniformly graded. None of the grain properties of gravels proved more significant than the others. Yet, open-graded gravel (dominant grain size 4-8 mm) containing a small amount (about10%) of sand fraction 0.06-0.6 mm, but with hardly any coarse sand (0.6-2 mm), was found to have good impact attenuation.

CONCLUSIONS: This study shows that the aggregates for shock-absorbing layer should always be tested wet in laboratory conditions corresponding the most critical situation. Standards should include a procedure for wet testing of aggregates.

© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.


Language: en

Keywords

child; playground; traumatic brain injury

NEW SEARCH


All SafetyLit records are available for automatic download to Zotero & Mendeley
Print