Construction work at 1201 Kennedy Road hummed along Thursday morning, with crews hauling materials from a roadside staging area about a quarter mile to the building site. The multistory structure is now visible from vantage points along Interstate 91 and Route 20. In an email, Town Manager Peter Souza said the project’s developer expects the complex to be “substantially completed” by the fourth quarter of 2021, though disruptive winter weather could affect that timeline. In June, the Town Council unanimously approved a three-year property tax abatement worth about $8.8 million for the building. Amazon is also in the process of converting a vacant industrial building on Helmsford Way into a package distribution center.