Image courtesy of Black & Veatch Black & Veatch's proposed new nine-story, $500-million global headquarters would be surrounded by a mixed-use district that the company says would add vibrancy and walkability to Overland Park, Kansas.  Black & Veatch is planning a $1.34-billion project to build a new world headquarters in Overland Park, Kan., and make it the anchor of a surrounding mixed-use development.  The 110-year-old engineering and construction firm plans to demolish its current 50-year-old headquarters building, construct a new $500-million structure on the same land, and add 700 multi-family housing units, 88 townhomes, a daycare, a hotel and a park in a multi-use district that would be called Overland Park Plaza II. Black & Veatch will serve as the master developer of the multi-use portion of the project which is expected to take 10 years to complete.…