| In recent years,timber-framed buildings have been widely promoted in China because of their environment-friendly characteristics and good seismic performance.However,timber-framed buildings are vulnerable to wind disaster damage and cause great economic losses,especially in the southeast coastal areas of China.At present,there are few researches on wind resistance of modern timber-structure buildings in China.In order to reduce the economic loss of timber-structure buildings damaged by typhoon,it is necessary to intensify the research on the wind-resistance performance of timber-structure buildings.The investigation shows that Roof To Wall Connections(RTWC)is the most vulnerable part of timber-structure buildings in high wind load area.Therefore,it is of great significance To study the mechanical properties of RTWCs in timber-structure buildings for the wind resistance design of timber-structure.In this thesis,RTWC nodes were connected by pegs with wood materials of Pinus sylva,Picea asperata and Douglas fir respectively,and nine types of RTWC nodes with two kinds of metal parts respectively connected with the pegs were the main research objects.Through unidirectional load tests,the failure modes and load displacement curves of each type of RTWC timber structure under single load were obtained,analyzed and compared respectively.Using eigenvalue analysis all specimens of the load-displacement curve was calculated,it was concluded that each time one of the biggest load,yield load and ultimate displacement and energy dissipation capacity,ductility coefficient,the initial stiffness of six characteristic value,the thorough analysis and comparison group,the failure mechanism of specimens under unidirectional load to metal fittings on the mechanical property of RTWC nail connection nodes enhanced relationships.Finally,the applicability of Foschi theory formula and Folz expression based on Foschi theory to RTWC node was explored based on the unidirectional load mechanical properties tests of three kinds of RTWC nail joints and six kinds of metal parts connected to RTWC nail joints,and a reasonable parameter determination method was established.According to the appropriate parameters,nine empirical formulas for connecting joints of timber roof and wall were established based on Foschi and Folz theoretical models.It provides theoretical reference and basis for the application of the connection between the wooden roof and the wall nail and the metal joint in the timber frame system,and had a certain guiding significance for the design of the connection node between the wooden roof and the wall.(1)With the increase of wood density in RTWC nodes,the initial stiffness,yield load and maximum load of RTWC nailed nodes increased accordingly;The ultimate displacement was mainly determined by the failure mode of the specimen,and the ultimate displacement of the specimen mainly due to brittle failure was small.The energy dissipation capacity of the RTWC nailed joint was not completely dependent on its density,but was jointly determined by the ultimate displacement and ultimate load,and had a positive correlation.(2)The connection performance of the TA group was better than that of the TB group,and the form of metal parts,the position of nails and the number of nails had significant effects on the joints.(3)The joints connected by Douglas fir have the best performance.The joints connected by the same metal parts have the following rules of maximum load and energy dissipation capacity: Douglas fir >,spruce >,and Pinus sylvata.Among them,the specimen of Douglas fir had a strong nail holding force,and the mechanical characteristic values of the metal pieces for the joint of spruce pin group were significantly improved.(4)The empirical formula of nine timberstructure roof and wall joints based on Foschi and Folz theoretical models was established,and the proposed empirical formula of timberstructure roof and wall joints could be used to simulate the load-displacement curve of the same type of RTWC joints. |
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