The Ordway Center is set to demolish its 306-seat McKnight Theatre to make way for a new 1,100-seat concert hall that would become primary home of the St. Paul Chamber Orchestra.

Teardown at the downtown St. Paul site will begin this summer, the Ordway confirmed Thursday.

The new concert hall, designed by HGA Architects, is due to open in spring 2015. Its circular design includes some seats located behind the musicians.

The project is financed by a $79 million campaign that includes $40 million for construction, $7 million in transition costs and a $32 million endowment to cover operating costs.

In December 2011, the Ordway announced that the campaign had already raised $60 million of its goal.

Plans for the new hall, announced several years ago, were pushed back to allow more time for fundraising. Now, however, preliminary work has begun on some backstage areas.

“We’re very close to where we want to be and we’ll be making an announcement in the weeks ahead,” said Ordway President and CEO Patricia Mitchell on Thursday.

The building project, which is under the aegis of a nonprofit group that includes the four principal users of the Ordway — the Minnesota Opera and the Schubert Club also perform there — comes at a time when the musicians of the SPCO have been locked out in a months-long labor dispute. In Minneapolis, locked-out Minnesota Orchestra musicians have complained about funds going to the renovation of Orchestra Hall while big salary cuts are on the table.

“We’ve met and worked with the architect as he designed the hall, and are real excited about it,” said SPCO trumpeter Lynn Erickson, a member of the musicians’ negotiating team. “But it’s frustrating to see the beginning of the new building when we don’t know if we’ll have a season next year or even an orchestra.”

The 1,900-seat Ordway opened Jan. 1, 1985, as a venue for its principal users. It will continue to house most events by the opera and Schubert Club.

From the beginning, the resident arts organizations competed for time. Musicians also have complained over the years about its acoustics.

“The challenges we’ve had at the Ordway are problems of success — too little time in the hall and not enough money,” Mitchell said. “This plan, which was suggested by the community, solves those issues. We have more time on the calendar and we have the endowment to cover structural costs.”