Danbury has approved an expansion for the Savings Bank of Danbury’s downtown redevelopment project. The bank will demolish a three-story building next to the former YMCA site on Main Street to create a landscaped common area for employees. It’s all part of the bank’s $17 million plan, which includes a new four-story office building. The project’s construction timeline has been delayed but is expected to take 14 to 18 months once started.