ASTM D7341-08

Full-scale bending testing is an effective way to determine flexural properties of structural glued laminated timber (glulam) beams. However, testing of large glulam members is cost prohibitive. Mathematical models, when confirmed by full-scale test results, are useful tools to assign flexural properties for glulam. This practice provides guidelines for sampling and testing full-scale glulam beams to determine their flexural properties and to validate mathematical models intended for use in assigning flexural design values.

1.1 This practice describes procedures for full scale testing of structural glued laminated timber (glulam) to determine or verify characteristic values used to calculate flexural design properties. Guidelines are given for: (1) testing individual structural glued laminated timber lay-ups (with no modeling), (2) testing individual glulam combinations (with limited modeling), and (3) validating models used to predict characteristic values.

1.2 This practice is limited to procedures for establishing flexural properties (MOR and MOE). Some of the principles for sampling and analysis presented may be applicable to other properties. However, other properties may require additional testing considerations that are beyond the scope of this practice.

1.3 This practice is not intended to supersede the provisions of Practice D 3737, but provides an alternative method for establishing characteristic values. Lay-up combinations developed in accordance with Practice D 3737 are not required to be governed by this standard.

Note 1—The models described by Practice D 3737 have been developed and modified based on more than 50 years of experience and many test programs. In some cases, however, it may be desirable to develop a new model based on other input properties or using lumber materials or grades not covered by that standard.

1.4 Details of production, inspection, and certification are beyond the scope of this document. However, for test results to be representative of production, quality control systems shall be in place to ensure consistent quality. Manufacturing shall conform to recognized manufacturing standards such as ANSI/AITC A190.1 or CSA O122.

1.5 Adjustments to characteristic values to determine reference values for design shall be in accordance with Practice D 2915 for allowable stress design (ASD) or Specification D 5457 for load and resistance factor design (LRFD).

1.6 Adjustments to ASD reference values for end-use conditions intended for design purposes shall be performed in accordance with Practice D 3737. The same adjustment factors shall apply to LRFD reference values, except that the ASD “load duration” factor shall be replaced by an appropriate LRFD “time effect” factor as determined in accordance with recognized industry practice.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.