11 Elementary Schools Have Major Flaws in Support Beams : Construction: A total of 50 buildings in the city will have to be repaired at a cost of $1.5 million. Students in summer schools will be transferred until work is finished.

Eleven San Diego city elementary schools are unsafe because of severe flaws in concrete roof support beams that could result in major damage from a strong local earthquake, Supt. Tom Payzant announced Thursday.

Although the school district began noticing potential problems about two weeks ago, well before last Sunday’s major temblors in the Big Bear and Yucca Valley areas, the recent quakes accentuated the district’s decision to “act with an abundance of caution,” Payzant said.

Students at two of the schools with continuing classes, Mason and Hickman elementary in Mira Mesa, will be relocated to other schools beginning next week until permanent repairs can be completed, Payzant said. Letters were sent home to all parents at the two schools Thursday. The 1,139 Mason students will attend nearby Mira Mesa High beginning Wednesday, and the 800 from Hickman will go to nearby Challenger Junior High.

No school will be occupied by students until it is brought up to full safety requirements, Payzant promised. He estimated total costs at about $1.5 million.

The affected schools are: Ericson, Hickman, Mason, Sandburg and Walker, all in Mira Mesa; Dailard and Green, both in San Carlos; Chesterton in Linda Vista; Penn in Paradise Hills; Spreckels in University City and Tierrasanta Elementary. Ericson, Penn, Tierrasanta and Walker are single-track, year-round schools that are scheduled to open July 27.

City schools architect James Geldert said Thursday that repairs can be completed on those schools before they open, given the high priority. Fifty buildings on the 11 campuses are affected. The schools have a total enrollment of almost 8,900 students, and several are among the largest elementary schools in the district.

All the schools were built in 1975 and 1976, using an identical, prestressed, precast concrete construction design. They are largely windowless structures because school officials at the time wanted large interior classroom spaces that could be subdivided into different-size “loft-style” classrooms depending on subject matter.

As a result, the schools are box-like structures with concrete “sheer walls” on each side connected to the precast concrete roof beams. Those walls are designed to take the force from the building during an earthquake and transmit it harmlessly to the ground.

But, during a chance inspection at Hickman Elementary earlier this month, administrators found cracks all along the connections between the beams and walls. Because of the similar building design and construction at the other schools, the district then made emergency checks at the 10 other campuses and found the same types of cracks there.

Geldert said the cracks indicated that the connections, which are critical for building integrity, have deteriorated to no more than 30% of the strength necessary to ride out a major earthquake. The district conducts spot checks of schools after major earthquakes, but officials said Thursday that the last such check, done in the summer of 1991, turned up no unusual signs at the 11 schools.

Repairs will involve “essentially building new connections” by drilling steel plates into the walls and beams, and then adding braces. “It will restore to 100% the structural integrity,” Geldert said.

The design of the schools is fairly common in the way precast concrete walls and roofs are used, Geldert said, leading him “to lean toward” the conclusion that a construction defect is responsible for the problems.

However, Geldert cautioned that officials have not yet reviewed all the documents concerning the 11 schools. That review is made more difficult because neither the construction company that built all the schools nor the subcontractor that provided all the concrete walls and roof beams is any longer in business, he said.

The structural engineer who worked on the schools is retired, but is providing information for the school district, Geldert said.

Payzant said the school district’s attorney is reviewing documents as well to see if the district can take legal action to recover the costs of repair from any of the parties.