Urgot's AA range is horrid. Using them as your main source of damage is the most suicidal thing you can ever do, and building attack speed will make it even worse when you try to use it. Urgot shreds armor, that's what he does, while being tanky as well.
He's no ADC, he's either an ADC replacement (please no), or a fantastic solo laner (god yes). Not only does his E reduce armor (20% at level 1, that's nothing to neglect), but adding a brut and LW will just make it even more horrible for the enemies.
Not to mention you getting up to 120 armor and MR at level 16 just by pressing R, with the price of potentially diving into the enemy team, but it's worth it if you get the target you want and live to tell the tail, which you will, cause hot damn, 120 armor and MR.
Core items would be Brut/black cleaver, LW, Manamune (stack that shit up and use the new active on muramana and just watch the reckage). A hextech gunblade is brilliant on him, way too many heals. then probably straight tankiness, anything from randuins to visage to GA to banshee's works.