A fairly long, quite high bridge stretching from rather steep and troublesome river slopes, with an arch in the middle and guard posts at both ends and fortifications anchoring the hostile side(mostly ruins today though and i cant really say how much was there at the relevant time)...
They will take it with great difficulty i think.
Not much trees to make rafts from either and the river is just too big to improvise a bridge to use for getting around the defense.
Ah interesting, it seems that the waterflow may also have been affected today because there is a hydropower dam just a few hundred meters upstream from the bridge.
8 minutes of video sweeps over the area.
Oh my, all the fortifications that we can see the ruins of today, if all of them existed at the time, that hill is one mean place to defend.
The steep slopes also makes that quite troublesome.
You would probably have to do the opposite, because the flanking force is the one that will have to deal with the fortifications at the end of the bridge. The walls there is in easy range of the end of the bridge for even a poor archer.
Which is why the defenders will of course have archers there. And with no accessway there, ladders is the order of the day.
By surprise, trickery, bribery or treason most likely.
Surprise: when coming there(before being known to be at the place), move fast and dont stop until you´re over the bridge and up the corner of the walls with enough soldiers. This has a major problem though and that is those very walls on the far side, if those can be manned quick enough before taken it could become a very onesided meatgrinder. And the length of the bridge means there will be quite some time to react. If cavalry is available, its easier, but they cant assault walls so not a huge difference.
Trickery: find a way, any way to get enough of the garrison to move over to your side and cut them off from retreating back across the bridge, then once the main force is gone, smash in the front door. Maybe use a part of the force to attack and then fake a chaotic retreat as if you had expected a much smaller garrison, with the rest of the force hidden(during the night perhaps) or out of sight but as close to the bridge as possible. Still, based on the terrain visible, im not sure this can be done.
Of course, all this depends greatly on what kind of force sizes, types and their qualities are involved.
If the garrison is of any real size, my personal choice would be cross the river elsewhere with the main force and attack the hill from the very opposite side once a smaller force(preferably at least 1.5 to 2 times the garrison in size, or they wont be take seriously) has engaged the defenders on the bridge.
That of course depends on there actually being another place not too far away where an army CAN cross.
Spears and swords or maces(or similar) with shields will probably be preferred for making the push, spears for the pushing across the bridge and swords/maces for assaulting fortifications.
If defenders have more than 1/3 of the attacking force in numbers(if even quality personnel), the attack will very likely fail.
If i had to take that bridge, deprived of surprise i would like at minimum a 5-1 force advantage, 10-1 preferred. Its a very troublesome place.