If you are building wooden bridge decks for loaded logging trucks, the correct tool is a gas engine driven auger bit. Looks and sounds a lot like a really big chainsaw. The wood is usually 12" x 12" and smaller but some spans use 16" x 16".
Open the doors at one end of the shop. Drive in with the loaded 18-wheeler of timbers. Lift up the load, truck drives out the other end of your "wood shop", set the load down. Build the bridge parts beside the load. Pick them up, new truck drives in under those, load up and head for the bridge site.