Shear strength and stiffness of glued-laminated timber made from European ash (Fraxinus excelsior L.)

The influence of size effects on the shear strength and stiffness of glued-laminated timber (GLT) made from European ash (Fraxinus excelsior L.) was assessed based on a comprehensive experimental campaign. The experiments were performed on full-scale GLT beams with rectangular cross-sections width × height = b × h = 120 × 480-800 mm², shear lengths L_v = 720-1500 mm, and ratios between the shear length L_v and the beam height h, i.e. α = L_v/h = 1.2-2.5. The influence of the test configuration (3-point bending and asymmetric 4-point bending) was also assessed. The obtained shear strengths of European ash GLT had mean values f_{v, mean} = 10.2 N·mm^-2 (coefficient of variation CoV_fv = 14%) and 12.2 N·mm^-2 (CoV_fv = 15%), for the 3-point and asymmetric 4-point bending test configurations, respectively. The shear strength showed some size dependency, with an exponent 1/m = 0.2 0.4 for a strength modification factor (600/h)^1/m as a function of the beam height h. The shear modulus showed no size dependency and the obtained mean values were G_mean = 1162 N∙mm^-2 (CoV_G = 6%) and 1120 N∙mm^-2 (CoV_G = 6%), for the 3-point and asymmetric 4-point bending tests, respectively.