Branches aren’t the only way JPMorgan Chase & Co. is building its presence in Pittsburgh. The nation’s largest bank on Tuesday confirmed exclusively to the Business Times that it is opening an office of J.P. Morgan Private Bank, which has been serving Pittsburgh clients for more than two decades but did not have a physical presence. The office, located in One Oxford Centre in downtown Pittsburgh, will open in early October, providing wealth management advice, strategies and services to individuals, family offices, foundations and endowments throughout the region.