Research On Stressed-Skin Effect Of Portal Frame Light Steel Structure

At present, steel structure of light-weight housing with gabled frames because of it has many advantages such as simple structure, high strength, light weight, short construction period and aesthetically pleasing, has been widely used. For this kind of building, pressed steel plate is often viewed as retaining structure. Even more, the stressed-skin effect of corrugated steel sheet can improve the overall stiffness. But now, with the technical reasons in our country, when carries on the engineering design, the stress of the main structure is considered and the existence of stressed-skin effect is ignored. This not only does not conform to the actual situation, but also may cause safety problems. For those reasons, this paper researches on the stressed-skin effect of portal frame light steel structure.In this paper, after reading a lot of articles about the effect of diaphragm, the author first analyzed the mechanism and conditions of stress diaphragm action, and summarized the research situation and methods. Then the basic principle of finite element theory are summarized and the equivalent method of diaphragm are analyzed particularly. In order to verify the correctness of this method, one experiment was also simulated by the author.In this article, the author uses the common dual slope portal frame light steel structure as an example for analysis. Four cases of four kinds of model is established, and then the static elastic calculation and modal analysis are made. Through the comparative analysis of calculation results of different models, we can get the following conclusions:The stressed-skin effect of portal frame light steel structure can improve the lateral stiffness of the structure and make the structure internal force distribution become more uniform and reasonable. It also can improve the bearing capacity of the overall structure and make the effect of support bar become smaller on the structure. However, it makes the mode of vibration more complicated. By comparing the steel weight between steel frame structure with diaphragm and without diaphragm, the result shows that considering the stressed-skin effect can reduce the components section size and weight under the same performance, and it has high economic value.At last, this paper uses a enclosed portal frame light steel structure as an example, some factors of stressed-skin effect such as slendemess ratio, thickness of diaphragms and hollow effect were analyzed. Through the comparative analysis, we can get the following conclusions:First of all, when the stressed-skin effect is considered, changing the slendemess ratio within the structure allows has a small effect on structural displacement. Secondly, increasing the thickness of the diaphragm can improve the lateral resistance and reduce the internal force of structure, but it is limited. Finally, with the increase of diaphragm hole area, stressed-skin effect will be decreased. And the hole which is located in the both ends of the side walls is more adverse to the stressed-skin effect than which in the middle.