WEI 121 Timber Design: Grading and Reference Design Values

by: Dr. Charles Chadwell, PE., Associate Professor, California State Polytechnic University, SLO

Module Length: 46 minutes

This module discusses wood defects and characteristics considered in lumber grading, determination of reference design values and labeling of wood members with a grade stamp.

The understanding of strength properties of natural material, such as wood, is essential to proper design of wood structures. This module explains how natural strength reducing characteristics of lumber are used to sort and grade it into different categories; and than, within these categories, how the reference design values of sawn lumber, used for engineering design, are determined.