The long-delayed Springfield Innovation Center at 270-276 Bridge St. got a $250,000 boost Wednesday. Construction has already resumed on the the $7 million renovation project, with completion expected by the end of December. Workers started back on the renovation project earlier this week, said Nicholas A. Fyntrilakis, chairman of DevelopSpringfield, which owns the building. He said the primary tenant, Valley Venture Mentors, should be ready to move in by the end of 2018. It might take longer for the Ground Up Cafe restaurant planned for the first floor to be ready.