The large portico was launched at the mausoleum on Eid al-Ghadir last year.
The Baab al-Qibla gate of the shrine was also reopened back then after restoration and decoration works.
The craftsmen working on the project preserved the historical shape of the structure.
The holy shrine of Hazrat Abbas (AS), which is close to the mausoleum of Imam Hussein (AS) in Karbala is a major pilgrimage site that attracts millions of pilgrims from around the world every year.
Following are photos of the ceremony, which was held on Thursday: