| Chinese ancient timber structures are our precious cultural heritage. The wenchuan earthquake and Lushan earthquake had brought an unprecedented disaster to ancient buildings which are in disaster areas. Therefore, reinforcement of the ancient timber structure building is extremely urgent. The reasonable reinforcement methods should not destroy its original force mechanism in order to achieve "repair old as old". Therefore, the study on force mechanism of mortise-tenon joint & column base and reinforcement methods has important theoretical significance and social value for better protection of the ancient timber structures. Through theoretical analysis, mechanical model of the straight tenon-mortise joint and column base joint is studied, and reinforcement method for tenon-mortise joint with damper is also discussed. The main contents and the achievements of this paper are summarized as follows:At first, the existing research results are classified, and draw the following conclusions:mortise-tenon joint has a half stiffness characteristic, but the value is still controversial. The Slipping between the column bases is Sliding Isolation, but its value has not been determined. Existing mainly reinforcement methods include flat steel and CFRP which have better reinforcement effect, but not the best method of reinforcement.Secondly, mechanics of the straight tenon-mortise joints under a loading loop is analyzed in detail. The theoretical model of M-6 relationship of the straight tenon-mortise joints is deduced from geometric condition, equilibrium condition and physical condition, considering the nonlinear compression property of wood and the pulling process of the tenon. The M-θ mechanical model curve is in good agreement with the experimental ones which prove that the model is correct. Top and bottom surfaces of the straight tenon-mortise joints contribute most to the bending stiffness. By mechanical analysis and solving math, getting the straight tenon-mortise joints feature points on the M-θ curve and giving a simplified three-fold mechanical model.Then, the stress mechanism of column bases connection were analyzed in detail, column bases connection be reduced to a level plinth connection spring unit. The establishment of the state of meshing and sliding state of dynamic equation identified two state transitions critical condition. Derive the maximum value of the column foot slip to give the relationship between the column and the column bottom horizontal shear slip foot maximum amount established mechanical model P-△ column bases connected..Finally, the suitable damper for ancient timber structures is be proposed. Based on the above mechanical model, Ya’an Guanyinge as the prototype, a finite element model is built and simulate the damper reinforcement. By numerical analysis, the conclusion is obtained that is the effect of the column foot sliding isolation is little and turning of the tenon nodes is the main energy-consuming role. The reinforcement of damper can provide additional damping in order to prevent drawing tenon and incline which is a good reinforcement method.In summary, the mortise-tenon joint and column bases has their special force transmission. The reinforcement of ancient timber structures does not only protect its appearance, but also mechanical mechanism. The reinforcement of damper can be better protection of ancient timber buildings under keeping its original stress mechanism which can provide a reference for the reinforcement of ancient timber buildings... |
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