Two 70-foot columns from the wreckage of the north tower were returned over the weekend to the lower Manhattan site.
On Tuesday afternoon, one column was hoisted onto a support base. The president of the 9/11 Memorial and Museum, Joe Daniels, said he expected the other one to be raised on Wednesday.
The 50-ton columns have three prongs and are known as tridents.
They made up the facade at the tower's entrance.
For the past few years they've been kept at a Kennedy Airport hangar.
The $45 million museum is being built below the 8-acre memorial plaza. It's set to open next year.
