Compression perpendicular-to-grain (C-Perp) is one of many structural design checks that must be made by the design engineer. Up until now, much of the effort in updating the Canadian timber design code, CSA-O86, has focused on the more prominent strength properties such as bending, tension and compression parallel-to-grain strength. With the increased use of machine stress rated (MSR) lumber in engineered wood products such as trusses, designers have encountered instances where design details must be revised in order to meet the compression perpendicular-to-grain requirements specified in the timber design code. Where design details cannot be revised, certain species of lumber cannot be used although these species are able to provide more than enough strength in bending, tension or compression parallel to the grain. Inconsistencies in C-Perp design resulting from code changes for the 1989 edition as well as developments in engineered wood products have made it necessary to review the design procedures for compression perpendicular-to-grain design. The aim of this project is to rationalise the design procedures and assist the CSA task group on C-Perp in updating design values for MSR S-P-F lumber. This task has been completed. The work has resulted in new design procedures and design values for compression perpendicular-to-grain in the 1994 edition of CSA-O86.1. A background paper on these changes was presented at the July 1994 meeting of CIB Working Commission (W18A) - Timber Structures in Sydney, Australia.
The report presents the verification of two truss analysis computer programs developed at Forintek. Validation consisted of comparing the computed truss deflections with the deflections measured from full scale truss tests conducted at Forintek. Issues which should be considered when modeling parallel chord trusses using either of the two computer models are discussed. A strategy for estimating lateral load sharing and composite action in flat roof and floor systems using these models with the Floor Analysis Program (FAP) is discussed.
Trusses - Computer simulation
Joints and fastenings - Strength - Computer simulation