Research On Material Properties Of Glubam And Its Application

With the development of global industry, the natural environment that we rely onfor existence has been badly influenced. It has to be admitted that building industryhas a significant influence on it. The production and application of steel and concretemake the environment even worse. Not to mention the dwindling area of vegetativecover, decreasing of forests and the worsing climate. Under such background, we needto look for eco-friendly construction materials, building methods and maintanencesystem. This dissertation studies the new bamboo composite—Glubam, focusing onits environmental performance, mechanical properties, and its application.Firstly, the concept of modern bamboo structure is introduced. Modern bamboostructure, which is developed on the basis of modern timber structure and steelstructure, adopts Glubam material as its main structural material. Glubam is a typicalglue laminated bamboo composites, and its development, production, and applicationare introduced in Chapter1.Glubam is only one of many laminated bamboo composites. For detailed andin-depth understanding of Glubam, glue laminated bamboo composites emerged inrelated researches and procedures are classified and introduced in Chapter2,including the characteristic, research and application.As a new construction material, Glubam’s environmental effect is a primaryconsideration. In Chapter3, some datum including producing, processing, andtransporting were obtained through investigation of a Glubam processing plant atYanlin, Hunan, China. As an example, datum about general producing energyconsumption and carbon dioxide emission were collected and analyzed. The resultsdemonstrate that both general energy consumption and carbon emission of Glubam arelower compared with other traditional construction materials including, steel,concrete, aluminum etc. In the mean time, some problems in processing of Glubamare found and suggestions are given for future development.In Chapter4, some basic mechanical properties of Glubam including tensilestrength, compressive strength, static bending strength, shear strength and modulusare studied experimentally. As Glubam is orthotropic material with bi-directionalorthogonal fibers, properties in two directions were both researched. According to thetesting results of Glubam and comparisons with other materials such as timber, timberbased composites and other glue laminated bamboo composites, Glubam is considered as a qualified and competitive construction material. Base on research of mechanicalproperties of Glubam and constitutive relationship of timber, the constitutiverelationship of Glubam is developed. Then, according to reduction coefficient oftimber and mechanical properties of Glubam, some adjustment is made and theallowable design stresses of Glubam are obtained to be used in design. And theResults showed mechanical properties of Glubam is competitive or even better thansome timber composites. Based on limit state design method in timber structure,standard values of strength for Glubam small clear specimens were adjusted to obtaintheir recommended values for ultimate strength design.After the research on basic mechanical properties of Glubam, off-axis tensiontest was conducted for the failure analysis of Glubam in Capter5. Based on Glubam’scharacteristic of being orthotropic with bi-directional orthogonal bamboo fibers,typical Glubam materials with fiber ratio of4:1were tested. According to the test data,and in view of the characteristic of bidirectional fiber in4:1Glubam, an advisedHankinson formula is developed based on some assumptions. And results showed theadvised Hankinson is good at predicting the off-axis tensile strength of4:1Glubam.Based on Glubam’s characteristic of being bi-directional, Tsai-Wu theory is used to doanalysis and corresponding failure envelop was obtained. Compared with test results,it is found that all test data except for which in main axis are all laid within failureenvelop because of its bidirectional fiber distribution. So a simplified method isdeveloped to explain and get the failure envelop of bidirectional Glubam material. Atthe end of this chapter, laminating properties of Glubam were analyzed considered aslaminated composites based on Classicial Laminated Theory (CLT).In Chapter6, Glubam single bolted joint is studied experimentally. Results showlongitudinal specimens present better ductility than transverse ones. And with theincrease of end distance and edge distance, bearing capacity of both longitudinal andtransverse specimens increases basically. Then specimens were analyzed theoreticallyand also through Ansys10.0. Results present that when edge distance iscomparatively small, the stiffness of side part and end part around bolted hole willalso decrease, which can lead to larger strain and makes the failure of specimen easier.With the increase of end distance, bearing strength of specimen increases. However,the increase of side distance doesn’t always lead to the increase of bearing capacity ofspecimen.Based on the above mentioned researches on constitutive characteristic,environmental performances, mechanical properties, failure performance and single bolted connection, Glubam is considered as a eco-friendly material, which can bebroadly used in construction and structures. At the same time, Glubam also needsmore development no matter in design, processing or application. But it is undeniablethat Glubam is a quite potential construction material. The research method, testingmethod and also the results from these studies are reliable and can be used in drawingup or revision of related codes and project applications.