竹木复合工字梁静曲蠕变性能评价

Evaluation of the Static Bending Creep of BambooWood Composited IBeam

  • 摘要: 为评价竹木复合工字梁(BWIB)的静曲蠕变性能和抗蠕变服役能力,借鉴美国标准ASTM D5055-04和ASTM D6815-02a检测分析BWIB的快速蠕变性能和90d蠕变性能。结果表明,BWIB的静曲蠕变符合木质材料的一般蠕变特征;BWIB 90d内发生的全程静曲蠕变挠度为533mm,其中,初始段(第1天)内发生的蠕变挠度为138mm,不可恢复的蠕变挠度为179mm,分别占试验全程静曲蠕变挠度的259%和336%;BWIB的快速静曲蠕变回弹率和90d静曲蠕变相对变形率分别为Φ=9105%和FD90=155,分别符合美国标准ASTM D5055-04规定的Φ≥900%和ASTM D6815-02a规定的FD90<20的要求;静曲蠕变对BWIB的静曲刚性无显著影响。

     

    Abstract: In order to evaluate the static bending creep (SBC) and service capacity in creepresistance of the bamboowood composited Ibeam (BWIB) which was selfdesigned and selfmade by the project, the rapid creep and 90day creep were tested and analyzed employing ASTM D50504 and ASTM D681502a. Results showed that the SBC of the BWIB accorded with the creep characteristics of common wood material. The total deflection of SBC of the BWIB in 90 days was 5.33 mm, in which the firstday deflection was 1.38mm and the irreversible deflection was 179 mm, which occupied 25.9% and 33.6% of the total 90day deflection respectively. Both the rate of the rapid recovery (Φ=9105%) and the 90day fractional deflection (FD90=155) of BWIB met the requirements of ASTM D5055-04, whose Φ≥90% and of ASTM D681502a, whose FD90<20. SBC had no significant effect on the bending rigidity of BWIB.

     

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