829 Continuing Study: Test of glulam beams with cracks to determine the shear strength

Published: 28 August 2012

The project will evaluate gluelam beams and test methods for the effect of cracks on shear strength. Tests performed are to be conducted on glulam beams to find out how different parameters (location of cracks, crack depth, etc.) affect shear strength.

Area: Industrial wood construction
Budget: 285 000kr
Duration: september 2011-dec 2012
Coordinator: Greger Lindgren, Martinson
Project Manager: Anna Pousette, SP Wood and Mats Ekevad, LTU

Background

There is a need to examine and test how shear strength is affected by cracks in
glulam beams and if so, how much.


Cracks in glulam beams reduces the strength but it is unknown how large the reduction is with respect to crack depth, crack length, etc. In the new Swedish version of Eurocode 5 for dimensioning of laminated timber, a KCR-factor = 0.67 is used to decrease the allowable shear stress due to the influence of cracks. It is believed that this is mainly affected by the shear cracks since the cracks preferably runs the grain. This factor represents a decrease compared to the previously used Swedish building codes.


In a series of tests, the shear strength of laminated wood without cracks determined and
reported including "Experimental and Numerical Investigation on the Shear
strength of glulam "by Crocetti et.al. Suitable test methods and results for glulam
are reported.

Purpose

The project concerns a continuing study evaluating the beams and test methods for the effect of cracks on shear strength. Tests are to be performed on glulam beams with cracks to determine the significance of the cracks on shear strength. The purpose of the tests is to find out how different parameters (location of cracks, crack depth, etc.) affect shear strength.

Final report

Previous projects in the field