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DERIVATION OF GRADE STRESSES FOR STRUCTURAL USE OF OSB

Objective

To determine by mechanical and physical test work supported by creep evaluation the structural grade stresses of European produced oriented strand board (OSB).

The proposed programme of research embraces a series of mechanical tests on medium sized test pieces as set out in a recent CEN document on the structural testing of board materials. This assessment will be carried out on boards of three thicknesses from each of the two producers.

Small scale tests will also be performed according to draft CEN methodology in order to derive a correlation between the two sizes of test specimens; this will then form the basis for quality control in production using the smaller size of test piece. Tests will also be performed to characterize the moisture resistance of the product.

The characteristic values derived from the medium sized test pieces will have to be modified by load duration factors as set out in EUROCODE 5. These factors will be obtained from an intensive investigation of the creep behaviour of the product. The characteristic values, modified in this way, are known as grade stresses which engineers can then use in structural calculations. Different aspects of the test programme will be carried out in three different laboratories. BRE will be concerned solely with quantifying creep behaviour, while CTBA and Surrey University will carry out complementary parts of the mechanical and physical assessment.

The method of sampling of test material will entail the random selection of consecutive pairs of boards.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Building Research Establishment (BRE)
Address
Bucknall's Lane Garston
WD2 7JR Watford
United Kingdom