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Title: Predicting bending strength of fire-retardant-treated plywood from screw-withdrawal tests

Source: (Research paper FPL-RP-568):20 p. : ill. ; 28 cm.

Author(s)Winandy, J. E.; Lebow, P. K.; Nelson, W.

Publication Year: 1998  View PDF »

Category: Research Papers

Abstract: This report describes the development of a test method and predictive model to estimate the residual bending strength of fire-retardant-treated plywood roof sheathing from measurement of screw-withdrawal force. The preferred test methodology is described in detail. Models were developed to predict loss in mean and lower prediction bounds for plywood bending strength as a function of a screw-withdrawal force. Our analysis of fire-retardant-treated plywood from three different studies, each with various fire-retardant-treatment, processing, plywood thickness, and exposure temperature groupings, clearly indicated that different fire-retardant-treatments and plywood thicknesses could not be grouped into a single buniversalc model. Nevertheless, some grouping was possible; parameter estimates for several grouped fire-retardant formulations and plywood thicknesses are reported for mean trends and lower prediction boundaries. Although the models were shown to acceptably predict plywood bending strength, additional work is needed to expand these models to address the effects of plywood quality, wood temperature, and moisture content at time of test.

Keywords: Plywood, Bending strength, Screwed joints, Fire retardants, Fire retardant treatment, FRT plywood

File size: 794 kb(s)

This publication is also viewable on Treesearch:  view
RITS Product ID: 20960
Current FPL Scientist associated with this product
Lebow, Patricia K.
Mathematical Statistician

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