The core items are Locket of the Iron Solaris and Ardent Censer because when you use the Locket of the Iron Solaris acrive you will put shield that will grant 15% attack speed and 30 magic damage per hit to all your allies around you, Ardent Censer pasive will work if Face of the mountain pasive and Shen's ult.Your ult scalling ap rations very well soo there are the AP RATIONs.

First start with the Relic Shield,next items will be Locket of the Iron Solaris and Ardent Censer wich are the core items, you can swich with mercury boots and swiftness boots,Randuin's Omen is a very good item and work well with tank champs like Shen.The last item can be Sunfire Cape if u need more armor and life,Spirit Visage for magic resist and ZZ'Rot Portal if u need to make preassure on others lanes.

That's my first build guys, i wish you all have a good day :D, ENJOY THE BUILD AND PLEASE RATE IT! :D