CHICAGOThe engineering firm Thornton Tomasetti Inc. has expanded and extended its lease at 330 North Wabash.

The company has amended its lease with Riverview Realty Partners at the 52-story tower, formerly known as the IBM Building. The building lost its moniker after the anchor moved out, and has undergone a large renovation, including the addition of a 316-room Langham Chicago Hotel on floors 2-13, scheduled to be open in the second quarter of 2013.

The lease amendment provides for the expansion of Thornton’s existing premises on the 15th floor, consisting of 25,045 sq. ft., so that its new premises will be the entire 15th floor consisting of 31,481 sq. ft. The term of the lease is also extended for an additional five years through Dec. 31, 2023.

Steve Baron, executive vice president of leasing at Riverview, said the amendment brings the building to 89.2 percent occupied. “The completion of this transaction continues our success in leasing the building toward full occupancy in light of the previously announced deals with tenants such as American Medical Association, Latham & Watkins, SmithBucklin Corp., BDO USA LLP, Patton & Ryan LLC and Burke, Warren, MacKay, and Serritella PC leases,” Baron said in a statement.

Stephen Eynon and Bradley Serot, senior vice presidents with CBRE Inc., represented the tenant in the lease amendment. Baron represented Riverview in the transaction.