Biology teacher Nina Petrasek works at Vaux High School in Philadelphia, pictured in the background Monday. Petrasek says the school, which is cutting staff and lengthening the school day, is under-resourced and should start by fixing more basic problems than dismissing teachers.

Philadelphia ? Even in a school system known for its academic troubles, the numbers at Vaux High School are jaw-dropping: More than 90 percent of 11th-graders tested last year could not read or do math at grade level.

But next fall, at least half the teachers at Vaux and 13 more of Philadelphia’s worst schools could be gone. And the school day, school week and school year could be longer.

While federal law has long allowed the overhaul of chronically failing schools, such extreme makeovers are likely to become more common because of more money from Washington, a growing consensus on education reform, and newfound willingness on the part of teacher unions to collaborate, experts say.

‘Really important signal’

“The fact that organized labor is now supporting and agreeing to more aggressive interventions in failing schools is a really important signal for this country, because historically that has not always been the case,” said Timothy Knowles, director of the University of Chicago’s Urban Education Institute.

Minnesota expects to remake 34 schools by the time students return next fall — more than the federal No Child Left Behind legislation did in the state since it was enacted in 2001. Philadelphia plans on transforming dozens in the coming years, and New Haven, Conn., has targeted some of its schools as well.

Such reforms help make districts eligible for money from the Obama administration’s Race to the Top, a

$4.35 billion competitive grant program to improve the nation’s schools. Districts seeking money to radically transform their worst schools must agree to staff overhauls.

Philadelphia’s turnaround effort, dubbed Renaissance Schools, is backed by a union contract approved last month that requires teachers at failing schools to reapply for their jobs; eliminates their seniority rights when it comes to rehiring them; and extends the school day by up to an hour, with the possibility of class up to two Saturdays a month and 22 days in July.

In exchange, all district teachers get raises, possible performance bonuses and the chance for a voice in the restructuring — or the choice of transferring to another school.

“None of us like to have anything imposed on us,” said Jerry Jordan, president of the Philadelphia Federation of Teachers, which represents about 11,000 teachers.

Competition encouraged

Teams of Philadelphia teachers and principals are being encouraged to compete with outside managers for five-year contracts to operate these schools. The district, with community involvement, will select the operators, which can then hire teachers without regard to seniority.

Union support for such flexibility and autonomy is crucial to success, said Superintendent Arlene Ackerman. In a largely failed 2002 turnaround attempt before Ackerman arrived, outside managers took over more than 40 failing schools with no involvement from staff or parents. Hampered by the union contract, managers couldn’t make big staff changes or restructure the school day; unhappy teachers sought transfers in droves.

Critics say Philadelphia’s contract doesn’t go far enough to attract teachers to its worst schools.

Operators can hire only those who apply, and the longer days may not appeal to the best and most experienced instructors, said Heidi Ramirez, director of Temple University’s Urban Education Collaborative and a former member of the city school board.

So far, 14 schools have been named turnaround candidates; the final list will be announced in March, followed by another group next year.

Most of the system’s 161,000 students come from poor households, and only half can read and do math at grade level.

At Vaux, where only 41 percent of students graduate, biology teacher Nina Petrasek said she would be crushed if she had to leave her students. She argued that the district should start by fixing more basic problems, from broken clocks, copiers and dismissal bells to shortages of textbooks.

“We are so under-resourced,” she said of the school, situated in a poor North Philadelphia neighborhood. “I’m not talking about luxury items.”