As for the glulam beams with plural round holes, there are very few studies at present. The authors conducted full-scale bending tests using 14 types of specimens and proposed the strength calculation methods of glulam beams with plural round holes based on the results of the tests. The ratio of hole diameter to beam height (d/h) are 0.3, 0.4 and 0.5. As a result, the relationship between cracking angle of holes and ratio of d/h was found. It was also found that the lower limit values of the effective section modulus at the hole could be approximated by using Hankinson’s formula.
