The article presents the methodology of modeling a footbridge structure made of a composite material. A lightweight composite footbridge is proposed, which may find application for small-span crossing of the rivers and other terrain obstacles for military purposes. The construction is characterized by lightweight, easiness of assembly and universal application in various location and conditions. The numerical model of the structure was developed based on a 6-meter prototype, for which a reinforcement was proposed and a detailed numerical analysis was carried out for the 18-meter version.