Model has a real-world scale, placed near (0,0,0) origin.
Object is at 100% scale.

Bridge clearance: 5.75m
Bridge height: 6.45 m
Bridge width: 3 m

Bridge is made with different objects, so you can easily change Bridge length; width; position and direction of the stairs (see thumbnails).

Scene contains Bridge objects in 'Bridge' layer and rendering setup in 'environment' layer.

No cleaning up necessary. Simply add model to scene and start rendering.

No subdivision used.

Ready to render as on thumbnails.

Textures used:
tiles.png 1068x1068
beton2.jpg 512x512
sky01_small.hdr 1024x512