The Social Security Administration is enhancing its presence in Oahu’s growing "second city" of Kapolei.

Local real estate development firm Avalon Development Co. LLC plans to break ground Monday on a new $8 million building for the federal agency.

The single-story building with 13,500 square feet of interior space and its own parking lot adjacent to the Kapolei Public Library and Kapolei Regional Park is projected to open in July.

The agency now leases space on the second floor of Halekuai Center across from Kapolei Shopping Center. The new site will allow Social Security offices to grow as the region’s population grows.

"Basically they were looking for a space they can grow into," said Avalon senior project manager Steven Kothenbeutel.

A representative of the Social Security Administration could not be reached for more details Wednesday.

Avalon will develop and lease the building to the agency, which will occupy the second piece of phased commercial development on a 3.8-acre parcel Avalon once envisioned for a pair of taller office buildings.

The Honolulu-based firm bought the parcel in 2006, and announced plans to develop a 335,000-square-foot office complex with a bit of retail in two buildings rising seven and 11 stories.

Dubbed Kapolei Pacific Center, the estimated $180 million project would have given downtown Kapolei its biggest building. But difficulties tied to an increasingly shaky economic environment scuttled plans to break ground in 2007.

Two competing office tower development projects for downtown Kapolei also never moved ahead.

Avalon instead looked to develop initial pieces of its property for smaller uses. A first phase became the two-story home of The Cole Academy, a preschool and child care center that opened a year ago.

After the Social Security Adminstration building is completed, about 2 acres of the Kapolei Pacific Center parcel will remain undeveloped and could still be used for more dense development, Kothenbeutel said.

"We still have a vision to go vertically on the block," he said, adding that market factors including office demand will help determine what gets built and when.