How to build Urgot and make him strong late game?
It's easy early/mid game you just E and Q the other guy to death but come late game it's kinda difficult for you to have high burst even with 45% cdr, the poke is still strong but 1v1 situation are usually quite unfavorable.
It's been a few months since I've really played him, but this is just my take on him back when I played a ton of him.
Since Urgot's DPS is strictly limited to his E-Q combo, which is relatively difficult to land on an important target, and the fact that you have no mobility, you're gonna be better off building tanky after BC/Manamune. That period in the midgame where everyone is only half built is where Urgot shines, get a gold lead and just become unkillable. Doing so allows to you force yourself onto the ADC or Assassin that you need to remove from the fight, deal respectable damage, and still survive. Yes, you COULD build IE/Triforce/Last Whisper Item/BT/<insert damage item> with no tank stats, but even if you land your E-Q, you're gonna get blown up in seconds. Yes you do have Damage Reduction and a massive Armor/MR boost on your ult, but it's usually not enough unless it's a 1v1 or 1v2.
So... While it's not really what you're asking, I recommend something along the lines of
Maybe mess around with 
