Experimental Study And Engineering Application Of Glue Laminated Bamboo Beams

Sustainability becomes the major concern of today’s society. Glubam (glue laminated bamboo) has emerged in such background, derived from the primary idea-"replace wood using bamboo’". Now glubam is related to all the aspects of construction including bridges, buildings, pavilions. It has a wide application, not only used for simple houses and temporary buildings in underdeveloped rural areas, but also applied for public buildings such as factories and schools.Based on the modern design concept, innovative construction technology and some industrial technologies for the wood, finger-joint Glubam beam has many advantages compared with other types of bamboo beams. For instance, it is easy to construct and to maintain, and it can have many different types. Finger-joint technology solves the dimension limitation of Glubam beam due to material. It has successfully been applied to the modern bamboo single house, bamboo prefabricated building, modern bamboo pedestrian bridge and modern bamboo vehicle Bridge. Since conventional knowledge for wood is not fully applicable to Glubam beam, deeper study such as stress strain relationship, node failure model, fatigue property for the bamboo beam in bridge and failure criterion of the bamboo beam under combination of bending and shear become the key topic for discussion. The basic physical and mechanical properties of the laminated bamboo, processing technology, engineering application, mechanics testing, failure theory of gluing bamboo beams are described in this thesis as follows.1. This thesis detailedly introduces the types division, processing technology and engineering application of Glubam beam. Depending on two typical examples of engineering application, a comprehensive display of component processing, bridge skeletion and design method is showed. Systematic safety analysis of the modern bamboo structure and durability of the bridges are verified by bridge test and long term observation. Then, the structure bearing capacity is carefully checked subject to the relevant codes. The Glubam bridge provides a substantial foundation for the application of Glubam beam with its advantages of simple molding technology, considerable economic performance, good safety and abundant raw materials.2. The section stress formula of Glubam beam under load (M. V) are described in the last chapter. Firstly, the situation of Glubam under bending moment and shear force is simplified; secondly, the formulas of stress distribution are displayed for pure bending and pure shear loading conditions. During the derivation, cross sectional conversion and equivalent method are employed to solve the shear stress distribution in finger-joint and the ultimate load of FRP beams. Based on the classical criterion formula Tsai-Wu failure criterion, the Glubam gluing bamboo is simplified as orthotropic materials and the general failure formula for Glubam beams under bending and shear loading is put forward. The feasible calculation model of FRP reinforced Glubam beam which bases on general structure network analysis is found3. This thesis briefly described the mechanical properties of Glubam which depend on the test results in related literature. Deriving from small clean specimen experiments, bolt connection tests and humidity tests, the overall performance of glue laminated bamboo were described and analyzed. What’s more, the regression formulas under any humidity condition are also listed, and creep calculation formula of Glubam is obtained subject to the Burger model in48th literature. Comparing the test results, it can be seen that the creep action weaken the bearing capacity and nonlinear stiffness of Glubam beam.4. Undering some basic assumptions, the strength and deflection calculation formula of Glubam beam are established through static tests, and the calculated results match experimental results well. It can be seen from the test results that the vertical bolt reinforcement measures in a certain extent reinforced the stiffness and strength of Glubam beam, while the FRP measures increased the bearing capacity of bamboo beam and the damage often occurred in compression area. Randomly selecting two group of specimens in the same batches of products which were used in vehicle bridge for the fatigue tests, it is obtained that the fatigue resistance performance of gluing bamboo beam is so good that contents the basic design requirement for50years servation. When the fatigue loads do not surpass the design value, the rigidity of test specimens does not descrease. Depend on the static test results-it is found that the fatigue tests slightly weaken the ultimate strength of the specimens. Hammer method of modal test has been further verified the fatigue effect on the stiffness and intensity of Glubam ejuine bamboo beam.To sum up.(?) is obvious that the Giubam beam has many advantages such as eminent mechanical properties, innovative design method of Glubam beam progress, economical and practical value. The experimental research and theoretical analysis of Glubam beam provide a reliable academic reference for promotion and application of bamboo, but also a data set for establishing and updating design codes and guidelines for future engineering applications.