竹集成材简支梁抗弯性能试验研究

摘要：基于15根竹集成材简支梁的抗弯试验，研究其作为结构构件时的抗弯性能。结果表明：竹集成材简支梁共存在3种主要的破坏形态，即梁底部竹片指接处脆性拉断、梁底部竹束胶合面斜向撕裂及梁底部竹纤维束逐渐拉断；竹梁破坏时的挠度已达梁跨度的1/50，若类同木梁采用梁跨度的1/250作为挠度限值，则可考虑以挠度作为控制指标进行构件设计；竹梁在破坏前，其横截面应变沿梁高度方向基本符合平截面假定；在加载初期，竹梁跨中截面曲率随外荷载基本呈线性变化，当弯矩达到极限弯矩的60%左右时，竹梁的截面曲率开始进入非线性阶段；随着曲率的增大，截面刚度逐渐退化，直至构件破坏。

关键词：竹集成材；简支梁；竹结构；抗弯性能；静力试验

中图分类号：TU366.1文献标志码：A

Experimental Study on Flexural Properties of Glued Laminated Bamboo

Simply Supported BeamsSU Yi， ZONG Shengjing， XU Dan， HUANG Dongsheng， ZHOU Aiping

（School of Civil Engineering， Nanjing Forestry University， Nanjing 210037， Jiangsu， China）Abstract： Fifteen glued laminated bamboo simply supported beams were tested to investigate flexural properties of glued laminated bamboo as structural components. The results show that glued laminated bamboo simply supported beams exhibit three kinds of typical failure modes， such as the brittle fingerpulloff at the bottom of bamboo beams， the oblique tear of bamboo gluing surface at the bottom of bamboo beams， and the gradually pull off of bamboo fiber bundle at the bottom of bamboo beams. The deflection of destroyed bamboo beams have reached 1/50 of beam span， which can be control indicator in structural design， as wooden beams deflection limit is 1/250 of beam span. Before the failure of bamboo beams， crosssection strain distribution along the height is in accord with the planesection assumption. At the preliminary stage of loading， curvature and loading of glued laminated bamboo beams have a linear relationship. When the moment reaches about 60% of ultimate moment， the curvature of bamboo beams enter the nonlinear stage. With the increase of curvature， the rigidity of the section gradually degenerates to failure.

Key words： glued laminated bamboo； simply supported beam； bamboo structure； flexural property； static test

0引言

木结构因轻质高强、建造周期短、抗震性能好以及生态宜居等诸多优点，成为国外住宅的主要结构形式[1]。然而，因历史上中国曾过度进行森林采伐，目前结构用木材资源匮乏，使木结构的应用受到了严重限制。竹结构具有与木结构类似的性能优势且竹子再生周期短，是一种可再生的生物质复合材料，近年来受到各国学者的广泛关注[214]。

竹子作为一种天然材料，已经有数千年的使用历史[15]。近年来，随着竹材工业的发展，竹材作为结构用材的研究及应用也取得较大的进展。吕雁等[1617]进行了竹胶合梁及竹质墙体研究，结果表明竹制梁和墙体的力学性能良好，竹制墙体还具有良好的保温和隔声性能，基于竹质结构构件的研究成果，在云南省屏边建造了竹结构小学校舍[18]。……