Answer to Question #330070 in Civil and Environmental Engineering for James

Question

A laminated beam is composed of three planks, two 175 mm x 80 mm on the outer sides with one 175 mm x 90 mm on the middle, glued together to form a section 175 mm wide by 250 mm high. The beam has a span of 3.50 m.

Allowable stresses:

Shear stress in the glue = 650 kPa

Shear stress in wood = 975 kPa

Flexural stress in wood = 8.75MPa

Find the uniform load that can be carried if

a) allowable shear stress in the glue is not to be exceeded

b) allowable shear stress in wood is not to be exceeded

c) allowable flexural stress in wood is not to be exceeded