Investigation Of The Fire Resistance For Kewitt Reticulated Shell Structures

In recent years,the application of the Kewitt shell structure in engineering has become more and more widespread.However,the poor fire resistance of the steel structures at present,research on the fire resistant design of the Kewitt shell structure is relatively weak in China,and the current relevant regulations on fire resistance is relatively poor.Therefore,it is of great theoretical significance and engineering practical value to study the fire performance and high temperature bearing capacity of the Kewitt shell structure.Based on the finite element numerical analysis and experimental verification of steel beam’s fire response,it is assumed that the fire source is located at the center of the Kewitt shell structure,and the nonlinear fire response of the Kewitt shell structure is studied.The influence of structural geometric parameters,material nonlinearity and other factors is considered,and the corresponding calculation method of high temperature bearing capacity is proposed.This paper has mainly completed by the following aspects:(1)The fire resistance performance of the steel beam under ISO temperature rise is analyzed,and the law of the low flange temperature and the mid-span deflection of the steel beam with time on the three sides under fire is obtained,and compared with the relevant test data.(2)The mechanical performance of the Kewitt shell structure during the heating process is analyzed,considering the effects of sagittal ratio,constraint conditions,initial defects,fire source power and fire retardant coatings.The analysis shows the influence law of relevant parameters.(3)Considering the protection effect of the fireproof coating on the components,the normal temperature and high temperature bearing capacity of the single layer Kewitt shell structure are compared and analyzed,and the simplified calculation formula for the high temperature stability bearing capacity of the structure.