重组竹梁长期受弯性能试验研究及蠕变分析

Experimental research and creep analysis of bending properties of bamboo scrimber beam under long-term load

为了解重组竹梁长期受弯性能,对3组重组竹简支梁进行了持续100 d的长期受弯性能试验,研究了碳化重组竹梁及未碳化重组竹梁的蠕变特征及规律,采用Burgers模型对试验梁的蠕变特征曲线进行了非线性拟合,得到了试验梁的蠕变特征函数。研究结果表明:重组竹试验梁在长期荷载作用下的变形经历了瞬时变形阶段、初始蠕变阶段和稳定蠕变阶段;随着时间的延长,变形不断增加,加载初期增长较快,进入稳定蠕变阶段后,变形趋于平缓;在30%极限荷载的持续荷载作用下,重组竹试验梁的变形最终趋于稳定;Burgers模型能较好地模拟重组竹梁的蠕变性能,碳化重组竹梁的蠕变总变形量、瞬时弹性变形量、粘性流动变形量、延迟弹性变形量均小于未碳化重组竹梁,同等条件下碳化重组竹梁在长期荷载作用下的挠度比未碳化重组竹梁减小20%。

Three bamboo scrimber simply supported beams were tested for long-term bending properties for 100 days.This paper studied the creep properties and laws of carbonized bamboo beam and non-carbonized bamboo beam.The creep properties of bamboo scrimber beam were analyzed by the long-term bending properties.The function relationship of creep properties was established based on Burgers model to analyze creep characteristic curve of specimen.Test results show that the deformation of the test beam undergoes instantaneous deformation,initial creep stage and stable creep stage.With the increase of time,the deformation of the test beam increases continuously,increases rapidly at the beginning of loading,and tends to be gentle after entering the stable creep stage.The deformation of bamboo scrimber beam finally tends to be stable under the continuous load of 30%ultimate load.Burgers model can fit creep properties of bamboo scrimber beam well.The total creep deformation,instantaneous elastic deformation,viscous flow deformation and delayed elastic deformation of carbonized bamboo beam are all less than those of non-carbonized bamboo beam.The deflection of carbonized bamboo beam under long-term load is 20%less than that of non-carbonized beam under the same condition.