Study On Mechanical Properties Of Typical Tenon And Mortise Joints In The Traditional Timber Structure Buildings

During the 13th Five Year Plan period,it is proposed to comprehensively implement the Rural Revitalization Strategy and deepen the rural reform.One of the important issues is to build new facilities,build new villages and towns,and improve the rural living environment.Most of the rural buildings in China are made of concrete,which lack of energy saving and seismic properties.The traditional Chinese wooden structure building combines the column and beam by mortise and mortise to form the bearing system of the building,which can dissipate the huge energy when the earthquake comes.The existing ancient wooden structure buildings are mostly distributed in the earthquake prone areas.Although affected by strong earthquakes,the unique structure system makes many buildings still stand up to now after hundreds of years.Therefore,rural buildings can learn from the tenon and mortise joint mode in traditional Chinese wooden structure buildings,so that the buildings have good seismic performance.When tenon mortise joint is used in the construction of wood structure building,the beam end is made into the shape of tenon and inserted into the mortise joint made by the column to form the tenon mortise joint.The long-term stress of mortise tenon joints will lead to the loosening of joints and the pulling out of tenons.These conditions will affect the stiffness,bearing capacity and energy dissipation capacity of wood structure buildings.Therefore,the mechanical properties of different mortise tenon joints are of great significance.In this thesis,four typical mortise and tenon types of wood members of Pinus sylvestris var.mongolica were studied.Each mortise and tenon joint member was made into two groups,one of which was added with sparrow.The effect of sparrow on the mechanical properties of typical mortise and tenon joints was compared.The physical and mechanical properties of Pinus sylvestris var.mongolica were studied,including bending strength,compressive strength along grain,transverse(local and overall)compressive strength,etc.;monotonic loading tests were carried out on four kinds of mortise tenon joints,and the control displacement of the joints was obtained.On the basis of displacement control,the loading tests of four typical tenon mortise joint wood members(with and without sparrow replacement)were carried out.The results show thesis:(1)Among the four typical tenon and mortise joints,the unidirectional straight tenon joint(DZ-1,DZ-2)has the best flexural stiffness.(2)From the Angle of stiffness value and absolute value of bending moment,the contribution order of the four kinds of mortise and tenon joints is half tenon > dovetail tenon >through tenon > one-way straight tenon.(3)The strength degradation coefficient of mortise and tenon joint specimens is between 0.6 and 1.3,and there is no obvious rule with the change of displacement amplitude.The existence of sparrow has no significant effect on the strength degradation coefficient.(4)The energy dissipation capacity of dovetail joint(YS-1,YS-2)is stronger than that of the other three types of mortise and tenon joint.For the type of half tenon joint(SB-1,SB-2)and dovetail joint(YS-1,YS-2),the energy storage capacity of the joint increased by83.5% and 57.1% respectively when the sparrow was increased.(5)The analysis of the stress state showed that the extrusion area of the straight tenon joint was the largest among the four tenon forms,while the upper half tenon of the half tenon was the most likely to pull out the tenon.The increase of sparrow was the most helpful for the tenon pulling of the half tenon joint.The tenon form of dovetail tenon was different from the other three forms.When rotating around the tenon,the pulling resistance was the strongest.The results of thesis can improve the damage problem of mortise and tenon joints of existing timber structure buildings,provide data support for the construction of rural residential timber structure buildings,and provide some reference for the renewal and design of timber structure dwellings in the future.