Disclosure: Rose Law Group represents Sunbelt Holdings. By Mike Sunnucks | Phoenix Business Journal Insurance company USAA and developer Sunbelt Holdings have started construction on a new 400-acre, mixed-use development in north Phoenix’s Norterra area. USAA owns the land, and Sunbelt is developing the project called Union Park at Norterra. It is located at 19th Avenue and Happy Valley Road next to USAA’s corporate campus …