CAMBRIDGE, MA—Having sidestepped a moratorium that quashed most commercial development here during the past two years, the Beal Cos. today broke ground on a 128,000-sf office building in the Kendall Square district. The six-story building is slated for completion next June.In addition to enclosed parking on the first two levels, the building will feature a corner courtyard park; covered shipping and loading docks and a variety of class A amenities. While she declined to identify specific suitors, director of leasing Molly Kimball Walker says she believes a large portion, if not all, of the space will be spoken for by opening day.Beal senior VP Peter B. Nichols notes that the building is one of the few to survive Cambridge’s stringent interim zoning plan. Difficulty in gaining permits is a key factor in the city’s super-tight vacancy rate, which is under 1% for office space. A recent industry report noted that there is currently just 13,000 sf available in the 11-million-sf Cambridge market, while rents are averaging $50 per sf. ADD Inc. of Cambridge designed the building; Perini Construction Co. is the contractor.