Work on renovating the Ayer-Shirley Regional High School complex on Washington Street is expected to begin in February, following the $56.6 million project’s approval on Nov. 17 by Ayer and Shirley voters. The measure prevailed in Ayer by a vote of 1,117 to 132; in Shirley, the vote was 936 to 438. The state will assume $37.2 million of the construction costs while the remainder, or $19.4 million, will be funded by the two towns. Final estimates on how much the average real estate tax bill will be increased in Ayer and Shirley over a 20-year period are still being worked out. The project is expected to take at least 2½ years to complete.