Oregon State University Graduate Student Workers struck this week to demand raises and maintain shorter union contracts.

Their union president says the institution continues to deny requests for raises while pushing for a longer contract, which would lock in lower offers from the university longer.

Austin Bosgraaf, president of the Graduate Employees Coalition, affiliated with the American Federation of Teachers, said his union has about 1,000 research and teaching assistants on the Corvallis campus who are dues-paying members. These graduate workers began striking Tuesday after more than a year of negotiations that failed to produce a contract, he said.

“These negotiations were very slow; the university was obstructive,” Bosgraaf said. He said he believed the university’s “double whammy of contract extension and insufficient salary proposal” had persuaded its members to leave their jobs.

The college’s lowest-paid graduates earn about $1,400 a month after taxes, and the union is demanding a 40 percent increase that would bring the lowest paid to the level of the average graduate salary, Bosgraaf said. In an email Thursday, a university spokesperson said the current minimum hourly wage is about $25 an hour and its most recent offer is a 14 percent increase. The university did not provide interviews.

“The university has negotiated a contract that both honors the important work of graduate employees and recognizes that as steward of public funds and student tuition, OSU must fulfill its obligation to manage the resources of appropriate manner,” the spokesperson wrote.

In addition to the remuneration, the duration of the proposed new contract The contract is a big deal for the graduate student union. Since the union was founded in the 1990s, Bosgraaf said, contracts have been for four years. He added that the contract, now expired, also included a “reopening” clause allowing for formal renegotiations on four articles of the contract every two years. Now, he said, the university is pushing for a five-year contract without reopening, and the union has countered with a three-year contract, also without that provision.

The university did not say Thursday how many classes had been canceled due to the strike or how many graduates were suspending work. Bosgraaf said it’s hard to say how many people are on strike, but there were 600 members on the picket line Tuesday and nearly 400 in pouring rain Wednesday.