The concrete monolith that currently sits at the corner of 148th Avenue Southeast and Main Street is one step closer to becoming the redeveloped Kelsey Creek Center that residents and city officials have envisioned for years.

Bellevue OK’d design plans for the center last week, a key component of the review process.

This represents a crucial step as the developers face a tight timeline of beginning construction next month, with a planned opening of sometime during the 2011 holiday season.

“We’re mobilizing for that,” said Nat Franklin of PMF Investments, the group that owns the property. “It’s critical we get started by mid-May at the latest.”

The developers still have several hurdles to clear before they can begin working on refurbishing the 105,000 square-foot old Kmart building, and the other properties on site. The appeal period for design review ends April 14. The project was scheduled to be put to the Hearing Examiner Thursday. Then it has to go through the City Council, and East Bellevue Community Council, which has shown enthusiasm about the project in previous meetings.

Mike Upston, the planner on the project, said the developers still have to obtain a number of permits, but those can be issued as other parts of construction are under way.

The project involves the renovation of the old buildings as well as pedestrian improvements to the site. A big part of the plan is to blend the shopping center with the adjacent residential neighborhood.

It remains unknown which tenants will take up the area, but the developers applied for a permit to install a health club last month. A grocery store likely will fill in the rest of the space in the Kmart location.

The second largest building is 76,000 square feet and will be renovated with a pedestrian path nearby. Two other buildings, one of which will be a fast-food tenant, and another a two-tenant retail space will round out the center, according to the staff report.

Another nearby property, the Shell station, is being developed by Key Bank, but it is separate from the property.

Several changes and conditions have been attached to the project following staff review. Construction will only be allowed between 7 a.m. and 6 p.m. during the day, and 9 a.m. to 6 p.m. on weekends.

Building designs will be more specific than previously indicated. According to the staff report, the property owner wanted to create generic buildings, allowing the tenants to influence design, but Bellevue wanted more specific and consistent designs that mesh with the surrounding businesses and neighborhood.

Developers will install a 10-foot screen in back of the loading dock behind the old Kmart facility to help in noise reduction. Overall, the changes aren’t significant enough to alter the project’s timeline.

“None of them involve the city asking them to change the project in a specific way,” Upston said. “We’ve been working directly with them on the timeline for the first couple critical permits and technical questions, so we can try to meet the needs they have.”