CHICAGO — Chicago Bridge & Iron Co. NV (CB&I) shareholders have approved the company’s proposed acquisition of Baton Rouge, La.-based Shaw Group Inc.

The Hague, Netherlands-based energy infrastructure company said Wednesday it expects the transaction to close in the first quarter of 2013, assuming remaining closing conditions are satisfied.

CB&I in July announced plans to acquire piping and structural steel fabricator Shaw as it looked to create one of the largest engineering and construction firms focused on the energy industry, including both fossil fuels and nuclear power. Among its varied services, Shaw provides maintenance services to the nuclear industry, CB&I said.

When the acquisition was announced, CB&I said that the combination of the two companies would provide growth opportunities.

Separately, CB&I said Thursday that it had been awarded an approximately $550-million contract by Esso Australia Resources Pty. Ltd. to engineer, procure materials for, fabricate and construct a gas conditioning plant in Longford, Australia.

"We are very pleased to be awarded this contract, which builds on our decades of experience working with ExxonMobil (Corp.) on a wide range of energy infrastructure projects around the world," CB&I president and chief executive officer Philip K. Asherman said in a statement.