Parameters Influencing Behavior of Diaphragms

Abstract

This paper presents a theoretical study of glue laminated lumber diaphragms. All glue lines are made up of elastomeric adhesives having stiffnesses of 90 psi‐900 psi. The use of such adhesives provides an incomplete partial composite. Three parameters which influence the behavior of diaphragms are studies. These include the stiffness of glue lines, the number of courses, and properties of the decking. Analytical results show that a large number of layers produces flexible diaphragms. It is also shown that gluing a few of the courses along the outer edges of the diaphragm may be sufficient to provide the proper strength and serviceability. In addition, the use of higher grade wood for the outer layers provides economical means of obtaining the strength required.