结构用胶合木性能若干影响因素

以落叶松、杉木为研究对象,研究了影响胶合木强度性能的齿顶宽、指接方向、指接单元等级、指接头、层积施胶量和压力等若干重要因素.试验选取744块落叶松锯材、2516块杉木锯材，采用2种结构用胶、5种齿长、2种指接单元等级、6种层积涂胶量、5种层积压力等作为指标变量，测试了指接材抗弯、抗拉强度和层积材的胶合性能.结果表明：指接材的强度不总是随齿长的增大而提高，其胶合后的强度主要受同截面内齿顶宽累积量所决定；垂直指接材的平向抗弯、顺纹抗拉强度不低于水平指接材，指接方向应由产品的承载方向确定；指接工艺不会降低大尺寸指接材的强度设计指标；层积施胶量和压力应与使用设备的实际产出相协调.

Factors Influencing Strength Properties of Structural Glulam

The important factors influencing the strength properties of glulam products including tip width, finger joint direction, unit grade, finger joint, glue application and laminating pressure were investigated using Chinese larch and fir wood. The 744 pieces of larch lumber and 2516 pieces of fir lumber were used. Different processing parameters including 2 kinds of glues, 5 finger lengths, 2 unit grade combinations, 6 glue application rates and 5 lamination pressures were adopted. The flexural and tensile strengths of finger jointed lumber and shear strength of laminated lumber were tested and evaluated. The results show that the strength of finger jointed lumber is not always increased with the increase of finger length and instead it depends on the cumulation of tip width in the same section area; the flatwise flexural strength and tensile strength parallel to grain of vertically finger jointed lumber are not lower than that of horizontally finger jointed lumber and the finger joint direction should be determined by future load direction on products; the finger jointing process does not lower the design values of larger size finger jointed lumber; the practical output of the production equipments should be considered in determining the laminated glue and pressure.