Statistical Analysis About Basic Wind And Snow Pressure And Research About Load Combinatorial Coefficient

In recent years, the global climate is deteriorating, disaster and collapse accident about large span steel structure is mainly caused by snow and occurs frequently, resulting in huge economic damage and casualties. Through investigation and analysis in the wind and snow disaster, we found that the largest value (next blizzard with winds), is often appear in the wind at the same time with snow, snow load so that local snow loads greatly exceed design load conditions, leading to a lot of large-span steel structure the occurrence of different degrees of destruction and collapsed, As in 2005shandong weihai snowstorms, in 2007 liaoning snow disaster, in 2008 China southern snow disaster, in 2009 hebei south-central blizzard disaster and in 2010, xinjiang snowstorm, etc.Basic snow pressure is the foudation in the calculating in snow load in the load code, the our country present the basic snow pressures from 1951 to 1995 survey data calculated case, is not really reflect the current load of the actual situation of the snow. To get more and more tally with the actual situation of snow load value in liaoning province, this paper has eight cities since 1951 to 2007 snow was investigated and analyzed, statistics a year most snow pressure value, seek accords with the actual load variation law of snow, a theoretical model with extreme type I (Gumbel) distribution of two different parameters estimation method of moment method and GengBeiEr method in the snow again pressure value of statistical, proposed sample series appear super-large value parameter modification method and fitting effect good parameter estimation method, and finally through comparison puts forward basic of wind pressure values are basic snow pressure reasonable Suggestions.Basic wind pressure is the foudation in the calculating in wind load in the load code, the paper statistics wind velocity data national and each district 159 city since 1951 to 2008,I statistic and analysis the maximum sustained winds for years with extreme type I (Gumbel) distribution and extremumâ…¢(Weibull) distribution type , by moment method, GengBeiEr method, variable substitution and least-square method in four different methods of parameter estimate separately calculated various regions of the country the basic wind pressure value .Through comparing the characterization parameter estimation optimal benign index confirmation best fitting effect of extreme value distribution and the optimal parameter estimation method, compares the basic code of wind pressure and this paper calculated value, I puts forward the basic snow pressure in the basic values of wind pressure on reasonable Suggestions This article introduces the load effect of combination rules, analyzes the specification about load combination value coefficient regulation. It will change over time in the load stochastic process presumed smooth binomial stochastic process on the basis of research wind load and snow load combination and combining the current specification design methods, further discusses the snow load of combinatorial coefficient, and through the nonlinear programming software Lingo realize to the reliability indexes, this paper puts forward a reasonable calculation of the snow load combination value coefficient, according to the results of analysis for structure design provides Suggestions.