American Society of Civil Engineers


Effectiveness of GFRP Sheets for Shear Strengthening of Timber


by Shaun Hay, (Res. Asst., Dept. of Civ. Engrg., Univ. of Manitoba, Winnipeg MB, Canada R3T 5V6), Kenton Thiessen, (Res. Asst., Dept. of Civ. Engrg., Univ. of Manitoba, Winnipeg MB, Canada R3T 5V6), Dagmar Svecova, (corresponding author), (Assoc. Prof., Dept. of Civ. Engrg., Univ. of Manitoba, Winnipeg MB, Canada R3T 5V6), and Baidar Bakht, (Consultant, JMBT Structures Res. Inc., 21 Whiteleaf Crescent, Scarborough ON, Canada M1V 3G1)

Journal of Composites for Construction, Vol. 10, No. 6, November/December 2006, pp. 483-491, (doi:  http://dx.doi.org/10.1061/(ASCE)1090-0268(2006)10:6(483))

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Document type: Journal Paper
Abstract: The objective of this study was to develop a cost-effective shear-strengthening technique for timber stringers that is environmentally friendly and leads to a durable structure. Testing was performed on creosote-treated Douglas fir beams, with dimensions of 100×400×3,650 mm, removed from a 40 year old bridge. Two strengthening schemes were investigated; incorporating vertical and diagonal glass fiber-reinforced polymer (GFRP) sheets applied to both shear spans. The diagonal scheme proved effective in increasing the average ultimate load, flexural stiffness, and deformability of the beams. Performance of the members reinforced using the vertical scheme, however, was poor compared to diagonally reinforced beams. The contribution of the diagonal sheets to the shear capacity of the stringers was around 12% at service loads and 40% at ultimate load. In conclusion, this study has shown that diagonal GFRP sheets are more effective than vertical sheets in shear-strengthening timber stringers with horizontal splits at their ends.


ASCE Subject Headings:
Fiber reinforced polymer
Rehabilitation
Reinforcement
Shear strength
Sheets
Timber construction