Fiddling With the Roof

The euphoria sweeping through 50,000 fans cheering as the Bank One Ballpark's roof retracted on opening day to unveil a crisp night sky splattered with fireworks came only after a $300,000 last-minute modification to the sensitive roof mechanism.

No one with the massive construction project knows whether the latest fix will be the last in a series of expensive problems that have vexed the nation's largest moving roof for more than a year and already have cost well more than $2 million in change orders and repairs.

Overall, the outlays for roof repairs and adjustments are a relatively small part of the $356 million ballpark. But about $20 million in additional bills, some related to roof problems, remain outstanding.

The possibility for even more extensive modifications and repairs to the retractable roof clearly exists.

"There is a potential dispute between the contractor and the owner," says Maricopa County Stadium District director Bob Williams. The stadium district owns the ballpark, which is operated by the Arizona Diamondbacks.

Stadium district records indicate significant structural deficiencies are present and that it will be several months before designers, contractors and engineers determine if the latest roof adjustments solved all the problems, or if more significant issues remain.

"Once we hit 115 degrees, we are going to know the answer," says a source close to the project.

Any costs to repair the roof during the first year of operation are the responsibility of the Arizona Diamondbacks. After the first year, any repairs costing more than $50,000 will come out of a long-term capital account, which currently has about $5 million, nearly all of which is taxpayer money.

The capital account received a windfall last winter when collections from the quarter-cent sales tax to finance stadium construction reached the mandated $238 million in mid-November. The sales tax, however, remained in place until December 1. Another $5 million was collected during the busy Christmas shopping season, raising taxpayers' contributions to the stadium to $243 million. The bonus $5 million was deposited in the ballpark's long-term capital account as required by agreements between the stadium district and the Diamondbacks.

If the roof continues to experience persistent problems into 1999, it could be taxpayer funds that are tapped first to cover further repairs, although it is more likely that the problems will be sorted out before then.

Contractors, engineers and designers could also face being held financially responsible for the roof's structural problems.

A survey of the roof conducted in mid-February revealed that the rails that span the north and south sides of the stadium on which the six roof panels roll are too close together, stadium district records show. In addition, the distance between the rails varies. The result is that the six movable roof panels mounted on six movable trusses do not sit squarely on the rails.

To fix the problem before opening day, workers adjusted several wheels, or bogies, attached to roof panels riding on the south rail. The process took several days, and, according to a source familiar with the work, was a success--but with a $300,000 bill. It was the second time in six months that adjustments were made to bogies on the south rail.

Questions remain as to how long the latest adjustment will hold. Not only are the rails not in the specified position, but there are problems with the trusses as well. The six movable trusses that hold up the roof and stretch between the north and south rails were supposed to be uniform but instead have up to a 2.75-inch variation in length, district records show. The 2.75-inch variation may not seem like much over a 517-foot span, but designers set a plus/minus one-fourth-inch tolerance for the trusses.

As summer heats up, the trusses will expand as much as two or three inches during daytime temperature extremes, before contracting as the temperature falls in the evening. It is uncertain how the temperature variations will impact the roof's operation and whether additional expensive adjustments to the bogies will be necessary or if other repairs will be needed.

What is known is that something fundamental is wrong.
"All parties are in agreement that no one yet knows, with any certainty, the reasons the rails are closer together than specified, or that the trusses are not the specified length, or that the trusses are skewed," Robert K. May, construction manager for Huber, Hunt & Nichols, Inc., stated in a March 3 letter to the stadium's primary contractor, Perini/Tutor-Saliba.

"These apparent deficiencies may turn out to be attributable to either construction or design issues. We do not believe there is enough currently available data, that when fully assembled and analyzed, the root cause of these apparent deficiencies could be determined. More than likely, additional information is required."

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John Dougherty
Contact: John Dougherty