Abstract: The mechanical properties and effective bearing cross-section of wood members of wood structure buildings are gradually reduced during fire, which may lead to local or overall collapse of the building and affect the fire fighting and rescue operations. In order to study the safety of the main load-bearing members of wood-frame buildings under fire, this paper takes the crossbeams of typical Chuandou and railing style residential buildings in Yunnan Province as the research object, establishes its three-sided fire model through ABAQUS, uses thermal-stress coupling to simulate and analyze the changes of its temperature field and mechanical properties, and obtains the ultimate loads under different fire exposure time. The results show that the ultimate load that a wooden beam can withstand under the action of fire is rapidly reduced, the fire resistance limit of load-bearing beams in fire for Chuandou residential buildings is 26 min; the fire resistance limit of load-bearing beams in fire for railing style buildings is 17 min.

Key words: wooden structures, wood components, fire safety, thermal-stress coupling, mechanical properties