水分对木质工字梁翼缘/腹板接口性能的影响

Effects of Moisture on Properties of Wood I-Beam

木质工字梁(Wood I-Beam,简称:IB)在使用过程中将不可避免地遇到潮湿环境的影响,研究水分对翼缘/腹板接口性能的影响,对确保IB接口最佳胶合状态以及最终产品尺寸稳定性至关重要.研究结果表明:IB的综合性纤维饱和点只有25%左右;含水率从8.9%提高到25%的接口的承压能力下降了47.2%,含水率从25%提高到53%的接口的承压能力仅下降了0.6%;水分对IB翼缘和腹板尺寸变化的影响是水分影响接口承载能力的间接因素;吸湿后接口的承载能力并不能恢复到吸湿前的初始水平;解吸至8.9%含水率的IB接口的承载能力比吸湿前同等含水率的IB接口低了17.8%.

The wood I-beam（IB） is constantly affected by the humid environment. In order to ensure the gluing effect and the size stability of final product, the research of the effect of moisture on the properties of IB joint is of great significance. The research results indicate that： 1） The comprehensive fiber saturation point （FSP） of IB is only about 25%;the bearing capacity of the joint declined 47.2% when moisture content（MC） increased from8.9%to 25%, the bearing capacity of the joint declined only 0.6% when moisture content increased from 25%to 53%. 2） The moisture effect on the flange and web dimension change is an indirect factor of moisture on properties of IB joint. 3） After the wet absorption, the carrying capacity cannot resume the initial level prior to wet absorption;the bearing capacity of the joint desorption to MC 8.9%is 17.8%lower than that of the same MC before wet absorption.