Study On The Seismic Performance Of Traditional Timber Frame With Seven-grade Materials Based On The Damage Of The Balustrade And The Purlin

The ancient Chinese traditional timber structure which contains the culture and tradition of the Chinese nation occupies a unique position in the history of world architecture.The existing remains of ancient buildings have rich historical and scientific research value.With the passage of time,the damage of ancient buildings continues to accumulate,which makes the protection and repair of ancient buildings imminent.It is the premise of scientific protection and reasonable repair of ancient buildings that the research on the mechanical properties of timber frame structure.Referring to the model test of the full-length single-span timber frame of seventh grade of wood,four types of single-span timber frame models with different combinations of Lan’e and Pu Pai Fang in ABAQUS were established.The finite element analysis of quasi-static test under reciprocating load and finite element analysis of dynamic performance under simple harmonic input were carried out on the models.The seismic performance,deformation and recovery capacity of timber frame under different Lan’e and Pu Pai Fang combinations were explored in this paper.The main conclusions are as follows:（1）The hysteresis curves of the four models all has a pinch effect.The skeleton curve,stiffness degradation curve and viscous damping coefficient showed that the increase of vertical load has a positive effect on the lateral resistance performance of the timber frame,but the energy dissipation capacity decreasesed accordingly.The quantitative evaluation indicators of the deformation recovery capacity of the timber frame(stiffness k_yiat the initial stage of horizontal displacement loading,displacement recovery coefficient,drift concentration factor)pointed out that the increase of vertical load has a positive impact on the deformation recovery performance of the timber frame.（2）The damage between Lan’e and Pu Pai Fang reduced the yield force and peak force,the yield force decreased by 9.07%at most.The stiffness and the energy dissipation capacity of the timber frame were reduced by the damage.The lateral resistance performance of the timber frame were adversely affected.The addition of Pu Pai Fang increased the yield force and peak force of the timber frame.The yield force increased by 28.13%at most,and the stiffness increased.The addition of Pu Pai Fang has a positive effect on the lateral resistance of the timber frame.（3）The damage between Lan’e and Pu Pai Fang increased the displacement recovery coefficient of the timber frame,which was up to 7.58 times higher than that of the intact timber frame;the stiffness k_yiat the initial stage of horizontal displacement loading decreased,by 27.78%at most.The k_yiof the frame without Pu Pai Fang was reduced,by 46.15%at most.The positive and negative drift concentration factor of the timber frame with Pu Pai Fang has symmetrical property,on the contrary the positive and negative drift concentration factor of timber frame without Pu Pai Fang were asymmetrical.The concentration trend of interstory displacement was more obvious when the timber frame without Pu Pai Fang were positively loaded,and the opposite were the case when it was negatively loaded.The addition of Pu Pai Fang has a positive impact on the deformation recovery ability of the timber frame.（4）The damage between Lan’e and Pu Pai Fang made the natural vibration period of the timber frame larger,with a maximum increase of 17.31%（gap 5mm）,the maximum damping ratio increased by 68.17%.The acceleration response became smaller,and the displacement response did not change significantly.The natural vibration period of the timber frame without Pu Pai Fang was larger than that of the frame with Pu Pai Fang,up to 9.96%,the damping ratio increased by 12.01%.The acceleration response and the peak relative displacement of the top decreased,but the displacement angle of the Dou Gong layer increased.