Abstract: The existing design and structure analysis of a girder hoisting machine refer to the design
code in general, but the unfavorable factors, such as the running rail irregularity, running
asynchronous, etc. are not considered in the process of design and structure analysis. These will even
cause the safety accident. Aiming at solving the safety problem of girder hoisting machine, the five
factors affecting structure safety are proposed based on the particular working condition, and three
values are selected in each factor. In order to scientific arrange the combination of the five factors for
structural safety assessment, the orthogonal design are introduced. The optimal combination scheme
of the five factors are obtained by using of the L9(34) orthogonal table. A MG450 type girder hoisting
machine was taken as example and the ANSYS was used to set up the element model. The
comparative of analysis results based on the working mode and the traditional design method was
carried out, and the effect of working mode was analyzed with experimental test. The analysis results
of girder hoisting machine based on working mode is coincide with the engineering practice.

Key words: girder hoisting machine, working mode, structure safety, finite element method;
orthogonal design