Material Test Of Old Wood And Mechanical Analysis Of Slotted Mortise-tension Joint Of Heritage Wood Frameworks

ABSTRACT:In our country, there are abundant Heritage buildings whose main bearing structure is wood frameworks. these types of ancient wooden buildings (abbreviation is heritage wood frameworks) have high achievement of architectural and structural technology, which is facing the problems of maintenance and sustainable utilization, and urgently need effectively repair measures and protection scheme. Heritage wood frameworks is spatial element wooden structure connected by mortise and tension joint, so that it can maintain high nonlinear and significant energy consumption property. Mortise-tension joint is complex coused by it’s structure、 material and friction mechanism, and is the key to slove problem of Heritage wood frameworks. In this paper, the material test and analysis of old wood sample have accomplished; The key parts of wood frameworks have induced, then analyzed mechanical properties of it’s slotted mortise-tension and make simplification to provide a reference for the frameworks structural system analysis.During the process of the microseismic test and joint measurement of Feiyun floor of Wanrong county in Shanxi Province, fragmentary samples of old wood are collectted. To solve the problem of undesirable requirement of standard material test, specially designed old wood small specimen is utilized to achieve the full process of old wood samples’ basic mechanical property. Through old wood sample’s morphology, density, texture and color, classified it’s oringinal component type. According to the test results of old wood small specimen, sum up and obtain the material model of old wood samples; Establish layer model which compounded by orthotropic elastic layer and GASKET layer, to simulate the transverse bearing capacity of old wood; The strength failure criterion is used to simulate the performance of ancient wood fracture.Combined with the field investigation and a large number of study materials of heritage wood frameworks, summarized and extracted the key parts from different wood frameworks, and determined it’s type and conformation. On the basis of the analysis of Yingxian Wood Tower’s structure system, analyzed and studied the mechanical properties of key parts’ slotted mortise-tenon joints, and build hybird linear element calculation model which is suitable for structural system analysis. Hybird linear element calculation model is composed of beam element, rigid element, semi-rigid unit, bearing element and fracture element, the required parameters are determined by the full-scale joint test.The calculation results can reflect the node tensile failure, the beam’s buckling and nonlinear properties of wood split, also can highlights the hysteretic behavior associated with the level of vertical load, and the calculation results is almost consistent with the test.