This was a significant problem that had the potential to trigger costly delays.
"We need to aggressively work together with all due speed to resolve the problems," stated a December 27, 1996, memo from Schuff Steel Company to the general contractor, Perini/Tutor-Saliba. At the same time, Schuff Steel asked Martin/Martin for advice on how to proceed.
A few weeks later, Martin/Martin had developed an alternative: Construction workers would bang the nuts tight with a wrench and a four-pound hammer. A test was designed to determine whether a worker using these hand tools could tighten the nut on a one-inch diameter Dywidag bar to reach a design specification of 26 kilopounds of torque.
The first test fell far short, topping out at 17 kilopounds. A week later, a second round of testing was conducted. This time the lubricant WD40 was sprayed on the Dywidag bar before the nuts were tightened. Using the WD40 allowed a worker to pound the nuts to 27 kilopounds of torque.
The same test was used on thicker-diameter Dywidag bars -- 11/4-inch and 13/8-inch bars. However, workers were only able to achieve 25.5 kilopounds of torque, far below the design specifications of 50 kilopounds for the 11/4-inch and 60 kilopounds for the 13/8-inch bar.
Nevertheless, Martin/Martin approved the hammer/WD40 method for securing nuts to Dywidag bars in February and March 1997, with several stipulations. The most important requirement was that "all tightening shall be done with full-time inspection. Bolts tightened without full-time inspection shall be removed, re-lubricated, and retighten[ed] with full-time inspection."
In an interview, Martin/Martin attorney Hartley Alley says each connection was inspected by the ballpark's field inspection company, ATL Incorporated. "A visual inspection is what's required for every single nut, and that's my understanding of what was done on every single nut by ATL," Alley says.
ATL president Frank Rivera declined to comment on the matter.
The stadium district and the team have not reviewed all of ATL's inspection records related to the approximately 1,500 Dywidag nuts throughout the ballpark.
The records that have been reviewed, however, appear to be inadequate.
Diamondbacks attorney "Brad [Holm] said that the ATL records are not very good, not very specific and are confusing," an October 5 memo prepared by Bob Williams states. "At the bottom line, Brad is not very optimistic that good records exist."
ATL's field inspection records had been long forgotten and packed away until Ramon Cook came crashing onto the scene last May.
Ramon Cook's May 16 letter set off a flurry of activity among the team, the engineers at Martin/Martin and the stadium's architect, Ellerbe Becket. Left notably out of the loop was the Maricopa County Stadium District, which owns the ballpark.
Cook, who did not return several phone calls placed to his home in Schertz, Texas, stated in his fax that the main cause for concern was whether the nuts were securely fastened to the Dywidag bars.
"I feel the Dywidag bars employed as anchorage for many life-safety-critical connections may be loose and ineffective as structural connections where they MUST ALWAYS be secure," he stated in his four-page letter.
Cook stated that Dywidag bars are designed with coarse threads making it relatively easy for the nuts to come loose, particularly when jarred by the vibrations of thousands of enthusiastic baseball fans. "I know this nature of this bar was badly misunderstood by all parties putting it into service in the Stadium we are working with today," he stated.
Worried that vibrations caused by jam-packed stands could cause the nuts to loosen, Cook recommended that the nuts be spot-welded to prevent them from "backing off," or starting to come loose.
Cook concluded his letter with a recommendation that "someone take action to prove or disprove my statements by examination of all the steel in the place. If ANY loosening is found ANYWHERE, all these thread-bar fasteners must be immediately made secure by any one of several available steel assembly methods."
Cook did not stop with the fax to the Diamondbacks. He also relayed his concerns by telephone to John R. Wasson, who as project coordinator directed construction of the stadium for the Diamondbacks. After conferring with Cook, Wasson sent a May 16 letter to Diamondbacks president Rich Dozer and team attorney Brad Holm "strongly" recommending that the Dywidag nuts "be physically inspected by a structural engineer to make sure that no loosening of the nuts has occurred."
Wasson repeated his recommendation a second time in the letter, concluding that the inspection should be done "as soon as possible." Contacted at his Hillsborough, California, office, Wasson declined to comment.