PITTSBURGH — The Pittsburgh Riverhounds are looking to the future with a major proposal to expand their stadium at Station Square, a move that team officials and local leaders say could revitalize the South Shore and bring significant economic benefits to the city. At a news conference Tuesday, the Riverhounds unveiled renderings for a proposed expansion that would transform their current venue into a 15,000-seat stadium. The new facility would meet U.S. Soccer’s Division I professional league standards and potentially host larger Division I college matches. The team estimates the project could generate at least $10 million annually for the city. The Riverhounds have applied to join Division I professional soccer, with a projected launch date of 2028.