In ScouseBoy's defence, you might want to carry cables (communications, power etc) across a gap like this, for example if the top of the rock was used for some military/navigation purpose.
But I cannot think of a purpose where you wouldn't also want to have human access, either for operation of the equipment or maintenance, so you would also need to provide an access bridge.
As a civil engineer, I can see a bridge with handrails, with paths leading up to at least one side. So for me it is a bridge intended to be used by people

Also, as I've mentioned already, the design and robustness of the walls suggest to me it is intended for use by the public, rather than the military or civil authorities.