Principal Financial Group Inc. will break ground this afternoon on a new office building in Cedar Falls. Ryan Companies U.S. Inc. will construct and own the 45,436-square-foot building, which will house more than 300 employees of Principal’s retirement and investor services division. The new facility at 1100 Technology Parkway, which will be smaller than the company’s existing building nearby, “will better match the needs of our workforce in Cedar Falls, but still leave the room for expanding staff if needed,” said Greg Burrows, senior vice president of retirement and investor services. Principal plans to lease the building from Ryan when it opens in July 2012.