| The formulation of Standard for design of timber structures(GB50005-2017)has created the necessary conditions for the popularization,application and development of wood structure building in China.But its content was mainly from the North American research results,these contents were not entirely applicable to the wood frame walls which used many domestic materials in engineering.In order to reduce the damage caused by lateral load to wood structure building,the research on reinforced design of wood frame wall has become an urgent task.In order to explore a new way to enhance the lateral resistance of wood frame walls,the antilateral properties and mechanism of the reinforced wood walls with diagonal-braced were studied systematically.Based on the quasi-static loading test method,the effects of tenon-mortis brace,herringbone brace,X brace,K brace and single brace on shear strength,elastic lateral stiffness,ultimate displacement,energy dissipation and failure mode of wood frame walls were studied emphatically,and the influence of vertical load,aspect ratio and wall panel on the lateral performance of wall was further studied on this basis.Meanwhile,in order to study the influence of different enhanced diagonal-braced on the lateral performance of wood frame walls,and apply the wood frame reinforced wall to the design practice.The experimental research,theoretical analysis and finite element simulation analysis were carried out from the aspects of nail bending resistance performance,nail joint connection performance,truss plate joint connection performance,and the anti-side performance of wall frame,wall unit and wall.The main research contents and conclusions were shown as follows:(1)The bending resistance performance of two kinds of domestic nails,the connection performance of panel nail j oints and frame nail j oints and the connection performance of truss plate joints of four shear types were studied by quasi-static monotonic loading test method.The shear as well as the pull-out bearing capacity of two kinds of domestic nails were studied emphatically.The results showed that the monotonic load-displacement curve had the characteristics of high nonlinearity and stiffness reduction,and there was no obvious elastic stage and yield stage.There was little difference between the ultimate displacement and the ultimate load of the transverse and longitudinal panel nail connections.In addition,the test value of shear ultimate strength of four kinds shear failure of truss plate was 3.26%?7.41%higher than the design value,which met the requirements of the formulation of wood structure design standard.Besides,two kinds of domestic nail connection characteristic exponential numerical models were established on the basis of Foschi exponential model,which provided the basic data for finite element simulation analysis of wood frame walls.(2)The corresponding hysteresis curve was established through the quasi-static cyclic loading test of 6 wall frames,comparison of the influence of tenon-mortis brace,herringbone brace,X brace,K brace and single brace on the lateral performance of the wall frames,as well as analysis of the failure form and force mechanism of the wall frame at different displacement angles.The results showed that the shear strength of the enhanced wall frame was 6.6-23.7 times higher than that of the standard wall frame,the elastic lateral stiffness was increased by 15.2?29.3 times,and the energy consumption was increased by 6.66?10.81 times.It was proved that the lateral performance of the frame of wood frame wall could be greatly improved because of the setting of diagonalbraced,thus providing a theoretical basis for the enhanced design of the wood frame wall.(3)The failure morphology and failure mechanism of six wood frame wall units under monotonic and cyclic loading were studied by means of quasi-static monotonic loading and cyclic loading program with the combination of variable amplitude and equal amplitude.The results showed that the monotonic load-displacement curves were more consistent with the first cyclic envelopes of cyclic thrust loading,and the shear strength,elastic lateral stiffness and energy consumption of the wall units can be greatly improved by five kinds of enhanced diagonal-braced.The vertical load played a role of anti-pulling anchorage parts similar to the corner,which could effectively restrain the lateral deformation of the wall units.(4)The influences of tenon-mortis brace,herringbone brace,X brace,K brace and single brace on the lateral resistance of the walls were studied by means of the monotonic and cyclic loading tests of six wood frame walls.The results showed that the unit shear strength,elastic lateral stiffness and energy dissipation of the reinforced wall were higher than that of the standard wall,and the smaller the height ratio of the wall with the same structure,the superior the lateral performance.Among them,the unit shear strength of the monotonic loading was increased by 10.54%?68.18%,the unit shear strength of the cyclic loading was increased by 11.09%?68.34%,the elastic lateral stiffness under monotonic loading was increased by 4.85%?45.45%,and the cyclic loading elastic lateral stiffness was increased by 5.37%?59.06%.The energy consumption of the wood frame walls was increased by 10.74%?55.29%,but the ultimate displacement of the reinforced walls was lower than that of the standard wall.The hysteretic characteristics and lateral resistance mechanism of wood frame walls were analyzed according to the variation rule and shape of hysteretic curve,and the horizontal load-displacement exponential numerical model of wall based on this structure was derived.(5)The wood frame walls were modeled and simulated to calculate their anti-side process with the finite element analysis software ANSYS by the directional coupling double spring and nail connection exponential models.The stress distribution,wall deformation and load-displacement curves of wood frame walls under the monotonic loading were analyzed emphatically,and the influences of enhanced diagonal-braced on the lateral performance and failure morphology of the walls were also discussed.The results of simulation analysis were in good agreement with the test results.The setting of enhanced diagonal-braced obviously improved the shear strength and elastic lateral stiffness of wood frame walls.It was proved that the nail connection exponential models could accurately analyze the lateral performance of wood frame walls under the monotonic loading,and provided the analysis basis for the reinforced design of wood frame walls.(6)From the point of the application of reinforced wood frame wall,the composition and load transfer of the wall anti-lateral force system as well as the precondition of the application of the structural design method were analyzed.According to the application mode and characteristics of reinforced wood frame walls,combined with the earthquake damage of wall.The reinforced walls were applied to both sides of doors and windows with large openings in the bottom of wood structure building,the lack of lateral support and the position of easy to be hit by loads,and the damaged walls replacement or reinforcement of old wood building.The influences of the change of wall structure and material proportion on the building performance were also studied,which provided a theoretical basis for the research of the anti-lateral properties and popularization of the reinforced wood frame walls. |
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