Crack Types and Characteristics of Timber Members in Ancient Building in North China
The cracking of timber members is one of the main damage in the timber structure of ancient buildings,which affects the safety performance of ancient buildings.To study the crack types and characteristics in timber members of ancient buildings,timber members from 8 ancient wooden structures in North China were evaluated through field investigation.The types,shapes,quantities,and sizes of cracks were recorded.The cracking of naturally-dried modern wood was monitored for a long time to obtain the long-term data.The results show that the cracking ratio in ancient building timber members is about 85%.According to the crack morphology and cracking causes,the cracks in timber members can be divided into dry-shrinkage cracks and stress cracks.The majority of cracks are dry-shrinkage cracks,which appeared away from the pith,and the proportion is 78.16%.The characteristics of drying-shrinkage cracks are mainly affected by the shape of timber members.The characteristics of cracks in both air-dried wood and ancient building wood are the same.After reaching equilibrium moisture content,the cracking characteristics rarely change.
ancient wooden structurescracked timber memberfield investigationtype and characteristic