Local development firm MW Group plans to build a third assisted-living rental complex on Oahu, a 156-bed facility in Moanalua.

The six-story project at 1280 Moanalualani Place will conduct a ceremonial groundbreaking on Friday and is projected to open in the fall of 2012.

The project, called the Plaza at Moanalua, will cater to seniors looking for an apartmentlike setting without a buy-in fee or mortgage. A range of personal care services is available, including care for people with Alzheimer’s, dementia or other memory disorders.

MW Group said it is responding to a growing population of Hawaii seniors who can no longer live at home independently but aren’t ready for a nursing home.

The Plaza at Moanalua follows two other similar projects by MW Group: the Plaza at Punchbowl, which opened in 2004, and the Plaza at Mililani, which opened last year.