INTERCHANGE BEING TESTED; ENGINEERS EXAMINE BRIDGE WELDS AT 5-14 FREEWAY CROSSINGS.

Byline: Charles F. Bostwick Staff Writer

The California Department of Transportation is testing welds inside support columns holding up the Golden State-Antelope Valley Freeway interchange, one of the last to be examined under a 3-year-old, statewide program launched after similar welds proved faulty in a San Diego Freeway interchange.

Caltrans engineers say the interchange is structurally sound, but they want to make sure the welded joints meet specifications for withstanding a major earthquake like either of the quakes that toppled the San Diego interchange in 1971 and 1994.

``The samples that we have tested so far have all done very well in terms of strength,'' Caltrans spokesman Jim Drago said in a recent interview.

Caltrans officials expect to know by early 2000 if any repairs are needed, he said.

Under a process that started earlier this year, a company hired by Caltrans is peeling off concrete and removing steel reinforcing bars containing welds at the Golden State-Antelope Valley Freeway interchange. The welds are then tested to make sure they withstand the pressures they were designed to hold.

So far, 15 welds have been tested and all have passed, Drago said. Another 15 remain to be tested.

The inspection work is proceeding very slowly because only a small section of the concrete and reinforcing bars can be removed at a time, Drago said. New bars are welded into place when the joints are removed for testing, he explained.

The interchange is among the last half-dozen of 299 freeway bridges tested because they contain steel reinforcing bars welded end-to-end at a bevel.

Of the 293 bridges inspected so far, repair work has been ordered only at the San Diego bridge, Drago said. Fines amounting to hundreds of thousands of dollars were levied against contractors whose work did not meet specifications, he added, and some contractors chose to redo their work rather than pay the fines.

Tests were ordered statewide after Caltrans inspectors in 1996 discovered that most welds were below par in construction at the intersection of Interstates 8 and 805 in San Diego.

Inspectors found welds that failed to meet specifications in many other bridges around California, but Caltrans officials concluded that those welds were in places where they would not diminish the bridges' strength in a quake.

``It was a financial issue, rather than a structural issue,'' Drago said.

Instead of ordering the welds removed, Caltrans fined the builders for substandard work, which drew complaints from builders who said they had done the work properly and were victims of changing Caltrans standards.