| As a traditional Chinese architectural form,Wood structure has been our precious architectural heritage and renowned all over the world.But after hundreds or even thousands of years,the overall structure and part of the components of the existing ancient architecture have produced different degrees of damage,and as a result of the perennial corrosion,moth,dry shrinkage and other effects,the mechanical indicators of wood are degradation with varying degrees.Its carrying performance needs to be properly assessed.Funded by the National Natural Science Foundation of China(51338001,51278324),this paper aim at the seven dengcai wood structure with four pillars in the 《ying zao fa shi》,studied the mechanical properties of Chinese traditional wood frame which characterized by the dovetail tenon and brackets under the horizontal cyclic load.(1)Aiming at the wood commonly used in ancient buildings,the Pinus sylvestris was selected as the material for the model machining and analysis.The density,moisture content,flexural strength,compressive strength,tensile strength,compressive elastic modulus,shear modulus and friction coefficientwere detailed tested.And the load-displacement curves of the material is obtained which can provide the basis for test and calculation analysis.(2)Considering the needs of this test,three kinds of displacement meters which called WD 、 WZ and WX were designed and manufactured independently.The displacement meters were used to measure the horizontal displacement and the vertical displacement of the structure,the deformation of the component and the relative deformation between the components.The calibration results show that the relationship between displacement and strain of WZ and WX displacement meter is linear within the measure range.While the relationship between displacement and strain of WD displacement meter is linear within 300 mm.(3)A 1: 2 scale model was used for the test.The vertical load was calculated according to a bucket roof and the concrete plate of equal quality were used to simulate the roof load.A self-made rocking column loading device was used to horizontal loading,so as to ensure that the load can maintain level and act on the same point in the process of the wood frame tilting.(4)The result of horizontal cyclic load test showed that:The column wooden frame has a obviously inclination during the frame movement.The movement mode of brackets and components above it are mainly translation.The components of brackets didn’t produce significant relative slip or damage.During uninstallation,the wooden frame can be restored to the balance position without external force.During the cyclic movement of the woodenframe,the tenon was periodically pull out and return,but didn’t appear out-of-tenon wreck.A significantly uplift appeared in the column feet,but didn’t slip.The component damage occurred in the junction of column,Lan’e and Pubaifang,as well as the dowels between Lan’e and Pubaifang.The hysteresis curve is not plump and the energy dissipation increase when the vertical load increases.The skeleton curve indicated that the increase of vertical load increases the stiffness and bearing capacity of wood frame.Besides,apparent stiffness degradation emerged with the increase of the horizontal displacement.(5)The ABAQUS finite element analysis results showed that : The deformation mechanism of the wooden frame obtained by software analysis is the same as the experimental result;There is a little difference between the two hysteresis curves,but the overall trend is the same and both of them are not full;The wood frame energy dissipation obtained by the software analysis is less than the test value. |
