The Steel Framework For Stability Practical Calculation Method

The stability of steel structure is a major problem in the field of steel structure. Unnecessary damages may happen If it can't be solved successfully. The elastic stability of steel frame structure is a prominent topic and its theories are relatively fully developed but there are still some imperfect aspects in it. So this article focuses on the current norm's weakness in elastic stability of plane steel frames and finds a reasonable standard to distinguish the two status of buckling models, furthermore it presents a convenient calculating formula for engineering design. The following are the main research procedures and achievements:1. Introducing the basic method for analyzing the structure flection load by finite units and giving a computer program.2. This article has made a fully study in the elastic stability of plane steel frames ,transforming the frame stability problem into a columnar one. With predecessor's help, we made a further consideration about the influences of the column's end rotation restricts,sway restricts on the same floor, and the rotation column restricts between the upper and the lower floor. A simplified calculating model is established and some buckling equations in the status of sway and non-sway are deduced by using the rotation displacement method under the condition of random sway resisting stiffness.3. This article analyzes the relationship of the calculating length of the steel frames under the condition of sway or non-sway . The threshold stiffness calculating formula is given by using the deduced stability equation.Detail Illustrations are also showed .On the base of studying the distinguishing standard ,in the condition of sway and non-sway ,which is prescribed by the ({The Norms Of Steel Frames Structure)) (GBJ17-88), we can see that it is reasonable to use the threshold stiffness of bacing to judge sway and non-sway through analyzing and comparing with the use of practical calculating example. Finally, a basic method is presented to tell the sway or non-sway of steel frames structure.4. Through further study of relationship between the critical load and bracing stiffness in the condition of sway buckling models of the steel frame structure, we deduce a field formula of sway buckling models of the steel frames structure in the condition of any sway resisting stiffness.After considering all sorts of influential factors, we give some amendments to the field practical calculating formula.