The column of Trajan was completed in AD 113 to commemorate the victory in the Dacian wars. This paper re-examines the meaning of two sacrificial scenes (86, 98-99), which have been interpreted as the pledge for victory. In scene 86, Trajan performs a sacrifice in front of a theatre in a harbour town, while he pours libations in front of the huge bridge over the Danube, allegedly constructed by Apollodorus of Damascus in scene 98-99. Before Trajan’s reign, sacrificial iconographies for the pledge of victory usually had a temple architecture in the background, which implies the gods to whom the sacrifices were dedicated. However, in the two chosen scenes, typical Roman architecture is represented in the background. I would argue that the two scenes represent not the pledge for victory but consecratio, a kind of sacrifice celebrating a building’s completion. The two scenes may also signify the praising of Trajan, who completed the great construction of Roman colonies. This characteristic also appears in other scenes on the column of Trajan, such as those showing the construction of roads, military camps and bridges, as well as in the inscription at the base of the column.