1.1 本规范提供了一种测试和评估木材和木质材料相对于可接受的荷载调整模型的荷载持续时间和蠕变效应的程序。本规范是为目前由共识标准涵盖的产品（例如木材、结构复合木材和结构用板材）制定的。本程序旨在证明工程等效于实践中规定的视觉分级木材的荷载和蠕变效应持续时间 第245天 对于在干燥使用条件下使用的评估产品。本程序不旨在评估冲击载荷下产品的性能。荷载或蠕变系数的特定持续时间的量化超出了本规范的范围。 有关本规范适用性的进一步指导，请参阅 X1.1条 在评注中。 1.2 使用本规范中的程序确定与规程的等效性 第245天 载荷关系的持续时间仅限于实木和木质产品，其长期载荷行为与实木相似。本规范中证明的等效性取决于对产品90天（最小）蠕变断裂性能的评估。在此评估中，必须满足三个标准:( 1. )90天内的足够强度( 2. )降低蠕变速率，以及( 3. )有限的分数偏转。这些标准及其背后的基本假设的发展概述见 附录X1和 附录X2 . 1.3 本规范未描述蠕变断裂模型未描述的长期退化现象（见注释 X1.2.4 ). 1.4 以英寸-磅单位表示的数值应视为标准值。括号中给出的数值是国际单位制的数学转换，仅供参考，不被视为标准。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。

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 D245 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 D245 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 specification (see Commentary X1.2.4 ). 1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.