| Due to problems in fire resistance design practice of petrochemistry steel frame structure, which brought by high temperature reflection of steel and high burn valuation of petrochemistry raw materials and products, The accidences with high fluquance in petrochemistry in resent years brouht high emphasis on reserch in fire resistence of petrochemistry steel structure. while dealing with limitation from complex mechanic problems, such as material unline in high temperature ect,this paper apply Plastic Upper-Bound Theory analysis several routine types structures of piper porch as whole .The analysis start from these structures possible destroy results,listing those possible destroy mechanisms and calculating their limmited loads (exterior loads or temperature) ,finding the minimum one from these limmited loads ,regarding the minimum one as the structure limmited load and regarding the mechanism it corresponds to as the result destroy form .This analysis method evites complex unline mechanic analysis,which contributes to lowing down the calculating difficulties and reducing calculating work, while compared to FEA (Finit Element Analysis) by ABAQUS, the method was proved be simple and practical .Appling this method to fire-resistence experience of steelframe structure of LanZhou petrochemistry LT.D, by optimizing the fire protection project, it also satisfied the performance design requirement. compared to the traditional prescription method and forreign merchant patent method, further more achieved fine economic saving.Listing of destroy mechanisms in this paper is effective to simple steelframes, while to multilayer and multispan structures, the linear programming math method should be invited to compage destroy mechanisms and calculate exterior load minimum ,under the help of computer program. the method of combining plastic upper-bound thoery with linear programing method in applying to fire-resistence design and anlysis of steelstructure was proved be effective and practical ,besidely simpling the fire-resistence work.This paper jioned the fire-resistence design and analysis of ethene porch steel frame structure from LanZhou petrochemistry LT.D, proving the optimizing procedure and results. |
