ALPHARETTA, GA. — Huntsville, Ala.-based Triad Properties has selected Atlanta-based Choate Construction to build a four-story, 106,000-square-foot medical office building in Alpharetta. The $26 million facility will be situated on a 11.7-acre site at the northeast corner of Old Milton Parkway and GA 400, which is adjacent to Northside Hospital’s 140-acre Alpharetta Medical Campus. The site will feature both the Class A medical office building and either an ambulatory care center or urgent care center.