The Burlington Fire Dept. evacuated six buildings at the intersection of Colchester Avenue and Fletcher Place due to a ruptured gas main.    “Burlington Public Works has doing construction when they ruptured a gas main on Colchester Ave.,” Battalion Chief Bourgeois said. “Burlington Electric is here to assist with power.”    Burlington Public Works, Burlington Electric, Vermont Gas, UVM and Burlington Police and seven fire trucks from Burlington Fire Department responded to the call.    The leak, on the north side of Colchester Avenue at Fletcher Place, continued for approximately 40 minutes before Vermont Gas could shut it off and replace the ruptured piping.    “[The firemen] knocked on the door, opened it up pretty much,” Fletcher Place resident and UVM senior David Boyd said. “After I had woken up, I heard this ‘wooshing’ sound. I could also very much smell the gas.”     Being the third gas leak in less than three weeks, many residents are questioning whether to blame coincidence or the competency of Burlington Public Works’ crews, Boyd said.