ATLANTA— Hardin Construction Co. is changing its leadership and ownership simultaneously, but two existing executives will remain at its helm. Earl L. Shell Jr., 68, Hardins chairman and CEO, is retiring after 40 years with the firm. He has been Hardins top executive for the past 20 years, and the first who was not part of the Hardin family. Shell, who had been the companys majority shareholder, began divesting his interests in the 1990s. He sold his last interest on Friday to other principals in the firm. Two other executives —- Brantley Barrow and Bill Pinto —- are now the construction firms top shareholders. Barrow, 52, who has been with Hardin for 27 years and most recently has served as vice chairman and chief financial officer, will assume the title of chairman. Pinto, 59, who has been with Hardin for 33 years, will continue as president. Hardin has decided to do away with the CEO title.