Seismic Performance of Damaged Dovetail Joints with Different Damaged Degrees in Timber Frames

Abstract

Themortiseandtenonjointsarethemainconnectionformsusedinancienttimberbuildings,anddamagedjointshaveacritical effectonthesafetyofatimberstructure.Therearethreemaindamagedcasesofdovetailjointswhicharepulling,contraction,and mixingdamages.Inthisstudy,usingatheoreticalanalysisofthestressdistributioninamortiseandtenonjointresultedfromthe pullout damage, a theoretical equation for the resisting moment of the joint was proposed. A finite element model was used to simulatethecyclicdisplacementloadingofaframewithintactjointsandwithdifferentlevelsofpullingandcontractiondamaged joints.Theresultsshowthatthemomentcapacitiesbothforthetestandthesimulationwereingoodagreementwitheachother. Thesimulationresultsalsoindicatedthattherearenochangesinthecapacityandenergydissipationofthepullingdamagedjoint comparedtothatoftheintactjoint,andgoodseismicperformancestillwasprovidedwhenthepullingdamagewaslessthan2/5of the joint length. However, the capacity of the contraction damaged joint was significantly reduced, and its seismic performance wastolerablylost.Theseismicperformanceofamixingdamagedtenonwiththesamedegreeofpullingdamagewasbetweenthat ofthepullingdamagedtenonandthecontractiondamagedtenon,andgenerally,itwascontrolledbythecontractiondamage.The friction between the tenon and the mortise is the main source of resisting moment and energy dissipation ability.