Since I’m not an Ansonia resident I have no clue where the 6th & 7th Wards are, but it looks from the map that you live on or near Franklin Street.
If you are referring to the Wakelee Avenue Reconstruction Project, the gas company and water company are asked, like all utilities, to upgrade their underground infrastructure before a state or federally funded project installs a new road bed, curbing and pavement surface. This is done in the two seasons before the actual construction project so that, hopefully, the brand-new road does not get dug up for a utility repair for at least 10 years.

If the gas company also upgraded their lines on adjacent streets (you said there were 20 streets with new pipe!) while they were out on Wakelee, the city wouldn’t have anything to do with that since cities are only responsible for sanitary and storm water sewers, not gas, electric or water utilities. Actually you are lucky if the gas company is replacing all of this piping. This section of Ansonia is originally one of the oldest sections of the original City of Derby and you have some of the oldest sections of gas pipe still in existence! It is way overdue for replacement.

Anyway, if this is the area you are referencing and the gas company is replacing pipe on lots of side streets, the gas company is responsible for replacing the pavement on those roads, but they wouldn’t do this until the city’s contractor on Wakelee gets to the end of their project (looks like Sept/Oct based on their progress). They should coordinate all paving at that time so that all roads would get their final top 2” of asphalt at roughly the same time to avoid having contractors drive heavy equipment over fresh pavement, ruining some of the new pavement surface.

Even if this isn’t the area you are inquiring about, I hope this answer is helpful to you.