... .52.7mmLength:10,20(3m,5.8m,6m)C purlin is the main structure in the bulding ... frame of the beamcomponents, studies have shown that ,for small and medium span in the door frame, ... if we adopt asingle limb C steel used for beam-column elements, the construction of the ... will be more convenient to components transportation, installation. C-beam flangewidth, nodes on the beam diameter bolts ...