In the following paper some aspects of numerical analysis and designing stages of a footbridge made of composite materials are elucidated. Because of the used materials the design process in this case is not ordinary and requires the development of concepts, material selections, identification of material properties, numerical simulations, strength calculations, serviceability and durability analyses. This contribution presents some aspects of the design process. The primary attention is focused on the method of estimating load capacity of a composite sandwich structure. Additionally, a selection of dimensions of the footbridge according to the regulations of the Polish Ministry of Infrastructure is presented. The main concepts of designing of the final form of the structure are discussed. Finally, the report compares two different finite element method models prepared to describe global behaviour of the structure. The models are based on shell and shell and solid finite elements.