Brazilian Timber Strength Grading and Strength Classes
Introduction Timber, as a natural material, is inherently variable; even within a single species. Strength grading overcomes this by assessing the strength and stiffness of individual pieces intended for structural use and assigning them to an appropriate strength grade and/or strength class which has known and dependable mechanical properties. A strength class is simply a group of species/strength grade combinations which have similar properties. The solid timber strength classes are defined in NBR7190:1997 Design of Timber Structures(in Portuguese). Eight classes are defined: three for softwoods, prefixed C, and five for hardwoods, prefixed D. The softwood strength classes are C20(weakest), C25 and C30. The hardwood strength classes are D20, D30, D40, D50 and D60. The numbers represent the characteristic compression parallel to grain stress for each strength class, a value which is used for designing to NBR7190:I997 which satisfy the requirements for each strength class and gives the appropriate design stresses and elastic module. This work presents the values of strength and stiffness properties of 50 Brazilian timber species related to the tropical and forested species used for civil construction in Brazil and its fixed strength class.
Carlito Calil Jr.
Sao Paulo University/Department of Structural Engineer, Professor, Sao Carlos, Sao Paulo, Brazil
国际会议
International Symposium on Wood Science and Technology(IAWPS 2008)(国际木材产品学会联合会2008学术研讨会)
哈尔滨
英文
197-198
2008-09-27（万方平台首次上网日期，不代表论文的发表时间）