The Research On The Effect Of The Braces And Its Location To Sidesway Resistance Of The Steel Frame

In the"Code for Design of Steel structure"(GB50017-2003) and Indian standard'Code of practice for general construction in steel (IS : 800-1984 second revision ) for steel frame, under the presupposition that braces should be continued in the vertical direction to ensure the rigidity of the whole frame, braces installing between columns are generally used to improve the stability of structures, that can reduce sideway of the overall frame, But in fact, during the course of designing, the brace sometimes can not be guaranteed to be continuous in the vertical direction for the limiting of the pipe line of the mechanical and the construction conditions, so the effectivity of the brace must be reduced. How to arrange the brace appropriately and adopt the corresponding form of brace when the other conditions are limited has not been studied and the design method is not available so that it may effect the rigidity and sideway of the structure. The main objective of this thesis is to determine the effect to stability of steel members when the brace is arranged at the different locations to reduce the sideway of the frame and stiffener the rigidity of the frame, then analyze the effect of the brace in the three-dimensional earthquake specially.In this thesis the FEM is used to analyze the steel frame, first adopt typical dual axle symmetrical H steel members to analyze under different loads including the basic earthquake and the limit earthquake, as the different location adjusted according to the variable value of stress ratio and the sideway, and the emphasis is analyzing the variation when the location of the braces is adjusted, we get the stress ratio sketch, history curve and the stress nephogram under the earthquake load, then from this we explain the effectivity of the braces and draw the reference conclusion for the steel design at last. Second, we analyze the earthquake response of the whole steel frame under the basic and limit earthquake load, comparing the history curve and the stress nephogram about the frame under the two-dimension and three-dimensional earthquake load, and conclude that three-dimensional earthquake analysis shall be carried out when the arrangement of the rigidity and the mass is non-uniform. In the end, the important suggestion is given comparing the design of the frame using China steel codes with Indian codes.Through the study in this thesis it is hoped to improve stability theory of steel frame and offer areference to the calculation of sideway resistance strength of steel frame with lateral brace.