Preliminary Span Tables for Traditionally Constructed Trusses

摘要

Traditional roof truss construction, which forms the largest single market for S.A. pine structural timber, and for which no clearly defined norms exist, are analysed according to the Code of Practice for the Design of Timber Structures, SABS 0163. Reasonable assumptions are made about the strength and stiffness of the connections, and all possible positions of support on internal walls are considered. Span tables for 4-bay and 6-bay Howe trusses for concrete tiles on battens are presented. These span tables give limiting safe spans for different sizes and grades of timber rafters and tie beams, and for different numbers of nails and bolts in the joints. Full construction details for the trusses and joints are provided.