Without seeing the details of these walkways or their exact location my first thoughts are that they will be of a lightweight steel construction. They will be made in 20/25m lengths in a factory. Brought to site and assembled into the finished unit on the ground. Then with whatever closures, diversions deemed necessary you crane them into position. You would need a 5 hour slot, approx to place one unit. Then with all your well prepared plans in place the day of the crane arrives and so does a westerly wind like our current weather.
Or if a concrete walkway is required you create a temporary working platform with all the safety features and build as normal with the set down area etc below you.