Parametric Studies on Inter-Column Brace Forces

摘要

In past studies on the design forces of inter-column braces, only the randomness of the initial imperfections of the columns was considered and the horizontal inter-column braces located at mid-height of columns were assumed to be effective only in compression. Actually, the initial imperfections of both the columns and the braces are random variables and the combination of the initial imperfections between them is also random. In this paper, the initial imperfections of the columns and the braces were randomly taken by Monte Carlo method, and a large number of the column-bracing systems with random combinations of the initial imperfections were modeled and analyzed by second-order analysis using finite element method. The binormal probability density function of bracing forces was found based on numerical calculations, parametric analyses and probability statistics. The results indicate that random combination of the initial imperfections between columns and braces leads to the randomness of horizontal inter-column brace forces in compression or in tension. The design forces of these braces have been obtained and a design formula has also been proposed. It is found that the design forces of these braces are smaller than those given in GB50017-2003, Eurocode 3 -1992 and AS4100-1998.