Applications And Development On Building Construction Using Continuous Purlin Of Cold-formed Steel Z-Sections

Cold-formed steel sections are lightweight material and suitable for building construction owing to their high structural performance and durability. At present, there are cold-formed steel C-and Z -sections using in the roof of building. When we study the continuous purlin and simply supported purlin, we find that the continuous purlin enhance more significative load-carrying capacity and stiffness than the simple-supported purlin. But it decreases effectively the weight of Cold-formed steel sections, so the continuous purlins are becoming more and more popular used. This paper summarizes the general characteristic and design principle of the continuous cold-formed steel purlins of the Z-section and introduces domestic and overseas development of the continuous cold-formed steel purlin of the Z- section, analyzes a variety of the factors effecting the continuous cold-formed steel purlin of the Z-section.In the light metal system of roof, continuous cold-formed steel purlins of the Z -sections are lapped each other in the rafter of roof. When we design the purlin of the metal roof, we made used of the continuous beam mechanic characteristic to find internal force. So we constructed an analytical mechanic model which is constructed by cell of beam, It tell us that how the moment is transferred in the lap joints. It is the analytical mechanic model of continuous beams that show characteristic of internal force really in the lap joints. This paperhave studied some questions which included distributed load, lapped length, becoming less crowded purlins each other in the lap joints, mechanic analysis, lateral buckling and ultimate load -carrying capacity and construction of double purlin in the lap joins. According to result of test and analysis of theories, the author advances the suggestions, which may be a reference to steel structure design.