Effect of an expansion-compression wave pair on free shear layer dynamics

A crossover or bridge for shipment as a compact unit for assembly at an installation site comprising a bridge section and a pair of stairways for connection with opposite ends of the bridge section. The bridge section is disposed in an elevated position relative to bottom ends of the stairways when assembled therewith for spanning an object. The bridge section comprises a pair of transversely spaced crossover panels with a grating or decking carried thereon. Readily assembled joint means are provided between the stairways and the bridge section at its opposite ends.