The CorpEd teacher contract that Weingarten and Christie helped to put together has expired, even though it remains in effect. I found this interesting detail in a piece at Huffington Post:
One major reason the union hasn't asked to start negotiations, he [union president, John Abeigon] said, is that the parties are waiting on an arbitrator's ruling on several grievances dealing with the old contract, including on retroactive pay for teachers who retired in 2012 and pay raises for getting advanced degrees. He said that teachers are getting the bumps only if they get new masters or doctoral degrees from one favored school, New York-based Relay Graduate School of Education. The union wants the district to give pay increases to teachers who earn graduate degrees elsewhere, too.