Glued laminated timber

Construction with sawn wood is limited by the size, shape, and characteristics of available trees. Lumber longer than 24 ft (7.2 m) or with a cross section dimension greater than 12 in. x 12 in. is difficult to obtain in large quantities. When lumber of these sizes is sawed, each piece much more often has some characteristic that seriously reduces strength or lowers the quality of its appearance than it is with pieces. Heavy timber construction and long spans are not feasible with sawn lumber. Sawn lumber cannot be bent into curves except in cross sections and is generally used straight.

However, structural members of any length and cross section and with any required curve can be made if pieces are glued together. The pieces, which are of standard lumber cross section, are glued one over the other, wide face to wide face, as laminations. No one lamination is as long as the member. They are glued end to end to reach the full length. A structural member made this way is called a glued-laminated member. The supporting members for heavy timber construction are glued-laminated timbers.

Lumber of 2 in. thickness is generally used for laminations. These laminations can be used straight in columns or beams and can be bent to form arches.

Notes:

end to end встык

glued-laminated member досчатоклеёные элементы

glued-laminated timber досчатоклеёные элементы деревянных конструкций

lamination n. слоистая конструкция

lumber n. пиломатериал

saw v. пилить

sawn wood пиломатериал

tree n. дерево, бревно

Ответьте на вопросы к тексту.

1. What are the limitations for construction with sawn wood?

2. Why is large size lumber not good for construction?

3. What is not feasible with sawn lumber?

4. How can structural members of any length and cross section be made of lumber?

5. How are lumber pieces glued to reach the full length?

6. What can laminations be used for?