A load-oriented and functional design of large structures is a major challenge due to the often insufficient available data about the exact load history. In this thesis a methodology is represented to optimize heavy-machinery-components. It is applied on a stationary metal-recycling-system by using experimental load analysis, assessment of local strains and comprehensive numerical calculations regarding shape and weight of the assembly. As a major result, an estimation of fatigue-life considering operational loads is shown. The structural loads that occur during operation were measured at significant points using strain gauges. This strain results were used to link measured stiffness to the simulation results of the assembly. Further on the operating pressures of the working cylinders were recorded and statistically evaluated as load spectra. Using these records, the local stresses in the global model and sub-models of characteristic components were determined, using the FE software package ABAQUS©. A comparison between the numerically calculated and the measured structural tensions provided an excellent match of results. Subsequently an evaluation of lifetime in the assistance with the tool FEMFAT© was done. The iterative structural optimization of the frame design was achieved by deactivating elements (Soft-Kill-Option) using the software TOSCA©. As an application example the given design space of a specific part was used as input data and further on optimized by minimum weight and maximum rigidity as target parameters. For the same numerically determined service lifetime a reduction of structural weight up to 40% (compared with the original design) was achieved by using this weight-optimization methodology.