What are the characteristics of beams in traditional buildings?

Beam is a cross component installed on the column in the building, and it is the most important part of the wood structure, bearing all the weight of the upper component and the roof. The beams in traditional buildings in China can be divided into three beams, five beams, seven beams, nine beams, one-step beam, two-step beam, riding door beam, moon beam, holding head beam and Taiping beam. The most common beams are five beams, seven beams and nine beams.