1. Scope

1.1 This specification provides a procedure for testing and evaluating duration of load and creep effects of wood and wood-based materials relative to an accepted duration of load adjustment model. This specification was created for products that are currently covered by a consensus standard (for example, lumber, structural composite lumber and structural-use panels). This procedure is intended to demonstrate the engineering equivalence to the duration of load and creep effects of visually graded lumber as specified in Practice D 245 for a product under evaluation used in dry service conditions. This procedure is not intended to evaluate the performance of products under impact loading. Quantification of specific duration of load or creep factors is beyond the scope of this specification. For further guidance regarding the applicability of this specification refer to X1.1 in the Commentary.

1.2 Use of the procedure in this specification to determine equivalence to the Practice D 245 duration of load relationship is limited to solid wood and wood-based products whose long term load behavior is similar to that of solid wood. Equivalence demonstrated in this specification is dependent upon evaluation of a product's 90-day (minimum) creep-rupture performance. In this evaluation, three criteria must be satisfied: ( 1 ) adequate strength over a 90-day period, ( 2 ) decreasing creep rate, and ( 3 ) limited fractional deflection. A summary of the development of these criteria and the underlying assumptions behind them is provided in the Commentary in Appendix X1 and Appendix X2.

1.3 Long term degradation phenomena not described by a creep-rupture model are not addressed in this standard (see Commentary X1.2.4).

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D9 Terminology Relating to Wood and Wood-Based Products

D198 Test Methods of Static Tests of Lumber in Structural Sizes

D245 Practice for Establishing Structural Grades and Related Allowable Properties for Visually Graded Lumber

D1037 Test Methods for Evaluating Properties of Wood-Base Fiber and Particle Panel Materials

D2915 Practice for Sampling and Data-Analysis for Structural Wood and Wood-Based Products

D3043 Test Methods for Structural Panels in Flexure

D4442 Test Methods for Direct Moisture Content Measurement of Wood and Wood-Base Materials

D4761 Test Methods for Mechanical Properties of Lumber and Wood-Base Structural Material

D5457 Specification for Computing Reference Resistance of Wood-Based Materials and Structural Connections for Load and Resistance Factor Design

E4 Practices for Force Verification of Testing Machines

E6 Terminology Relating to Methods of Mechanical Testing

E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods

Keywords

creep rate; creep-rupture; duration of load; fractional deflection; lumber; structural composite lumber; structural-use panels; Duration of load; Fractional deflection; Lumber--specifications; Structural composite lumber (SCL)--specifications; Structural-use panels; Wood products--specifications; Creep deflection; Creep rupture; Creep strain rate; Dry conditioning/testing;

ICS Code

ICS Number Code 79.080 (Semi-manufactures of timber)

DOI: 10.1520/D6815-02

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