Federal and state officials in Rhode Island kicked off a major project Monday to replace two bridges that carry Interstate 95 through the heart of Providence. Governor Lincoln Chafee, the state’s congressional delegation, Mayor Angel Taveras, and others participated in a groundbreaking ceremony for the Providence Viaduct project. Two new spans will be built to replace the deteriorating bridges that carry I-95 near Providence Place Mall. The original bridges were built in 1964. The work is expected to cost nearly $150 million and stretch into late 2018. Construction will be done in phases in an effort to minimize disruptions. The state will pay 20 percent of the cost, with federal money being used for the rest. The Viaduct carries some 220,000 vehicles a day along the edge of downtown Providence, over the Amtrak tracks and the Woonasquatucket River, connecting to the interchange with Routes 6 and 10. It is one of the busiest stretches of interstate highway in the Northeast.