Glubam胶合竹梁试验研究及工程应用

发布时间：2018-04-17 17:37

本文选题：Glubam胶合竹梁 + 指接　；参考：《湖南大学》2013年博士论文

【摘要】：在全球能源不断减少和世界节能减排思想的不断蔓延的国际大环境下,土木工程领域中的Glubam胶合竹梁从初步的“以竹代木”构想逐步发展成为涉及桥梁、房屋、大型场馆等各个方面的新型结构构件。在不发达国家的农村和乡镇里,Glubam胶合竹梁沿用了木结构的发展历程,不仅可以用来建造简易住宅和临时建筑,还成功应用到厂房、学校等公共建筑领域。 Glubam胶合竹梁是参照胶合木工业技术,应用现代设计理念和工艺技术开发的一种新型承重构件。指接技术的引入使得竹梁的加工不受原材料尺寸的限制,并且使板材的对接更加紧密和牢固。指接胶合竹梁不同于其他形式的竹梁,具有加工简单、形式多样、维护简便等优点。在成功将指接胶合竹梁应用到现代竹结构单体房屋、竹结构活动房、现代竹结构人行桥梁和车行桥梁之后,常规的力学性能研究已经极大的限制了竹梁应用的推广,胶合竹的应力应变关系、指接节点失效模型、桥梁中竹梁的疲劳性能和竹梁弯剪荷载条件下的失效准则都是亟待解决的问题。本文对Glubam胶合竹梁的加工工艺、失效理论研究、基本物理力学性能、力学试验研究、工程应用等方面分别进行了阐述,具体工作如下： 1.本文详细介绍了竹木结构的发展历程以及Glubam胶合竹梁的种类划分、加工工艺和工程应用,论述了新型竹材梁的研发现状和使用情况。通过两个典型的工程应用实例,展示了现代竹结构桥梁的构件加工、结构形式和设计方法。通过成桥试验和长期观测,分析了现代竹结构桥梁的安全性和耐久性,并结合相关规范对结构承载力进行验算。简单的成型技术、可观的经济性、良好的安全性以及丰富的原材料为Glubam胶合竹梁在桥梁中的推广和使用奠定了基础,也为改进胶合竹的结构性能研究和开发更优化的结构体系提供了参考。 2.从失效准则基本理论出发,论述了各向异性材料的经典准则公式Tsai-Wu的参数和适应范围。结合Glubam胶合竹梁交织状构造和分层结构的特点,推算出Glubam胶合竹梁在平面应力状态下的一般失效公式,将复杂各向异性材料的三向应力问题转化为简单的平面应力问题。通过数值计算方法推导Glubam胶合竹梁在荷载(M,V)下的截面应力公式。对工程使用中四种胶合竹梁的受力情况进行分析,得到各自的极限承载力的计算公式。其中普通胶合竹梁忽略胶合层的不连续性,采用纯材料连续介质计算方法：指接胶合竹梁可将指接层和非指接层分别进行应力分析,然后利用力平衡关系算出中性轴位置,最后得出竹梁承载力。 3.参考国内外相关文献,总结了有关胶合竹材的一系列试验成果,简单描述了其力学性能方面的特性及物理力学指标,为胶合竹梁的强度和刚度研究提供了基础的理论依据。参考木结构物理力学试验规范和美国NDS设计规范,引用胶合竹抗压、抗拉、抗弯和抗剪试验、胶合竹徐变试验、螺栓连接方式性能试验以及前人做的竹材干湿度试验,对胶合竹的整体性能进行阐述和分析,并通过回归拟合得到任意湿度条件下竹材的弹性模量计算公式。采用Burger模型对胶合竹梁的蠕变性能进行模拟,通过蠕变试验后的静力破坏试验以及回归拟合,可以得到Glubam胶合竹梁的蠕变变形计算公式。试验证明荷载的长期作用会在一定程度上降低竹梁的承载能力与非线性阶段的刚度。通过考虑含水率、材料变异、徐变、天然缺陷、应力集中等参数影响,对试验结果进行修正后得到Glubam胶合竹梁的容许设计应力。 4.通过Glubam胶合竹梁静载试验,对比不同连接方式、叠合方式、FRP增强措施对竹梁承载力和刚度的影响,并基于几点基本假设,建立了竹胶合梁强度和挠度等计算公式。引入Glubam胶合竹梁的相关试验数据与计算结果进行对比,可以发现Glubam胶合竹梁的计算模型能够很好的估计构件的承载能力,为工程应用提供可靠的计算依据。在已建成的现代竹结构车行桥梁同批次产品中,随机抽取一组胶合竹梁试件进行试验。将200万次反复荷载试验后的试验组试件与对比组试件的试验结果进行对比后发现,胶合竹梁抗疲劳性能良好,能够满足桥梁设计的50年使用期限的基本要求。试验组试件的疲劳荷载在不超过设计荷载的条件下,试件刚度无明显下降。通过静载破坏试验的结果对比,发现疲劳试验对试件的极限强度有少许削弱。疲劳试验对Glubam胶合竹梁的刚度和强度的影响在锤击法激励的模态试验中得到了进一步的验证。本文通过对Glubam胶合竹梁进行一系列的试验研究后发现：Glubam胶合竹梁具有良好的抗弯能力和疲劳性能；其抗弯试验结果能够很好地验证其承载力计算公式,为竹结构桥梁的荷载计算提供重要依据；对Glubam胶合竹梁的试验分析和理论研究为胶合竹的推广和应用提供了可靠的学术参考,也为相关规范的编制和工程应用提供了依据。
[Abstract]:Glubam glued bamboo beams in the field of civil engineering are gradually developed into new structural components involving bridges , houses , large venues , etc . In the rural and rural areas of the developed countries , Glubam glued bamboo beams along with the development of wood structure can not only be used for the construction of simple houses and temporary buildings , but also successfully applied to public buildings , such as buildings and schools .

Glubam glued bamboo beam is a new type of load - bearing member , which is developed by using modern design concept and process technology by referring to glued wood industrial technology . The introduction of finger joint technology makes the processing of bamboo beam not limited by the size of raw material , and makes the butt joint more compact and firm .

1 . The development course of bamboo wood structure and the classification , processing technology and application of Glubam glued bamboo beam are introduced in detail in this paper . The present situation and application of new bamboo beam are discussed . Through two typical examples of engineering application , this paper presents the structural form and design method of the modern bamboo structure bridge . Through the bridge test and long - term observation , the paper analyses the safety and durability of modern bamboo structure bridge , lays a foundation for the promotion and use of Glubam glueing bamboo beam in bridge , and provides a reference for improving the structural performance of glued bamboo and developing more optimized structural system .

2 . Based on the basic theory of failure criterion , the general failure formula of Glubam glued bamboo beam under load ( M , V ) is deduced . The formula of cross section stress of Glubam glued bamboo beam under load ( M , V ) is deduced .

3 . A series of experimental results of glued bamboo are summarized by referring to the relevant literatures at home and abroad . The mechanical properties and physical mechanical indexes of the glued bamboo beams are simply described . The formulas for calculating the creep deformation of the glued bamboo beams are described . The experimental results show that the long - term action of the load can reduce the load - carrying capacity and the stiffness of the non - linear stage . The experimental results are modified to obtain the allowable design stress of Glubam glueing bamboo beams .

4 . Based on the comparison between the experimental data of Glubam glued bamboo beam and the calculation results , it is found that the calculation model of Glubam glued bamboo beam can be used to estimate the bearing capacity of the beam and provide reliable calculation basis for engineering application . The experimental results show that the fatigue test has a little weakening on the ultimate strength of the test piece . The influence of fatigue test on the rigidity and strength of Glubam glueing bamboo beam is further verified in the modal test excited by the hammering method .

After a series of experiments on Glubam glueing bamboo beam , it is found that Glubam glueing bamboo beam has good bending resistance and fatigue property .
The calculation formula of its bearing capacity can be well verified by the bending test results , which provides an important basis for the load calculation of the bamboo structure bridge ;
The experimental and theoretical research on Glubam glued bamboo beam provides a reliable academic reference for the promotion and application of glued bamboo , and provides a basis for the compilation and engineering application of related specifications .

【学位授予单位】：湖南大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU366.3

【参考文献】