Construction Flaws Cited in Tank Rupture

Design and construction errors caused the water-tank rupture that sent a 6-foot-high wall of water crashing into a Westminster townhouse complex and fire station Sept. 21, according to a report released Tuesday by city officials.

But because the tank was built 30 years ago, the city has no legal recourse, officials said--neither the manufacturer nor the contractor is still in business, and the statute of limitations for such action has long since run out.

“It’s very hard to go back at this point and say which guy it is. Is it the designer, the contractor or the inspector?” city Public Works Director Brad Fowler said.

The tank’s foundation was missing critical “hairpin” steel bars to help the concrete walls withstand the pressure of 5 million gallons of water, according to the 400-page report by the Pasadena office of Montgomery Watson, an engineering firm hired by the city to investigate the incident.

Architectural drawings made after the tank was built in 1967 indicate that the hairpins were present, but the engineering company could find no trace of their having been installed.

Some missing drawings also make it difficult to assign blame, officials said.

Contributing to the rupture was the misplacement of a reinforcing steel tendon in an inner section of the tank’s circular foundation, the report stated. It concluded that the misplaced tendon and the missing hairpins allowed the concrete to crack, and water seeping through over the years corroded the steel.

That allowed the tank’s walls to dislodge from the base, sending the water rushing down Hefley Street, the report concluded. The rupture injured six people and displaced more than 30 families. City officials estimated the damage at nearly $30 million.

Ashok Dhingra, vice president of Montgomery Watson, said the city followed proper procedures when inspecting and repairing the tank over the years.

“Could the city have known about this? The answer is no,” Dhingra said. “There was no way to figure out there was any impending failure.”

Westminster officials said there are three other tanks of similar design in use in Orange County: two in Santa Ana and one in San Clemente. The placement of the steel tendons was done properly on those other tanks, Fowler said, but the only way to find if they have the hairpins is through imaging devices such as an X-ray.

Westminster officials said they will send copies of the engineering report to the other cities to help them evaluate their tanks.

The report also stated the damaged tank is beyond repair and should be demolished. Deputy City Atty. Kimberly Hall-Barlow said that will not be done, though, until insurance companies and residents have an opportunity to conduct their own engineering studies.

Westminster officials have not decided what to do with the city’s other water tank, which is similar in design and construction to the one that ruptured. Located at Monroe and 23rd streets, that structure could be retrofitted, Montgomery Watson stated in its report.

The second tank was drained soon after the rupture.

One new tank could be completed as soon as August 1999 if construction were to start soon, Fowler said. Depending on the type and size, it could cost $5.3 million to $10.4 million.