COSTA MESA — The Planning Commission on Monday unanimously approved plans to build an upscale gym at Triangle Square, a step that the shopping center's new owners hope will get the once-thriving center back in shape.

But the approval wasn't without doubts and questions about whether there's enough parking to handle the flow of gym-goers, especially during peak hours.

Greenlaw Partners, the center's owner, hopes to fill the partially vacant Triangle Square with other high-end tenants, and executives have said they find the parking there adequate.

The proposed club will not replace the existing 24 Hour Fitness at 555 W. 19th St. — less than half a mile away.

The new gym would be the fourth 24 Hour Fitness in the city but branded as a higher-end "super sport" facility that charges more for memberships and offers towel service and other amenities.

The San Ramon, Calif.-based fitness club chain offers three tier services: active clubs pricing ($29 a month), sport clubs pricing ($39 a month) and super sport clubs pricing ($54 a month), said Steve Datte, regional vice president of 24 Hour Fitness.

The proposed 24 Hour Fitness is expected to attract customers who will frequent the center's upscale tenants, according to Greenlaw officials.

A parking study conducted by the applicant found that there will be more than enough spaces for its customers. But at least two city planning commissioners expressed concerns that there would not be enough spaces if the center is filled with retailers and restaurants.

It's hard to determine whether there will be shortage of parking once Triangle Square is fully occupied, because the city still doesn't know which type of tenants will be occupying the center, said Mel Lee, Costa Mesa senior planner.