Martin/Martin developed an additional assembly--called a horizontal guide roller--to steer the movable roof panels. The system took several months to design, fabricate and install. Records indicate the revision cost more than $1 million. Preliminary tests on the west roof panels indicate the revision is working.
Besides installing the guide roller, Martin/Martin continually changed the location of wheels on which the roof panels ride. By August, Schuff Steel once again was complaining loudly.
"As we have previously advised the problems associated with the roof are not the responsibility of Schuff Steel," Savage states in an August 12 memo to Perini/Tutor-Saliba. "Schuff will no longer proceed with the work required for the revised design location for the bogies (wheels) without written direction."
Continuing revisions in the field led to Martin/Martin's October threat to stop working until its overdue invoices were paid.
That same month, a potential disaster was averted.
In early October, workers began tightening the cables that will be used to pull the movable roof panels open and shut. The "pretensioning" work was designed to tighten the cables to 30,000 pounds of tension.
Schuff Steel expressed concern because it had not been able to review the procedure to tighten the cables.
"This work activity was not anticipated in the design of temporary bracing and could impact loads beyond the capabilities of the bracing," an October 17 Schuff memo stated.
The memo continued with a warning in bold print: "Failure of the bracing could result in catastrophic failure of the roof system."
Martin/Martin intervened and developed a plan for the cable tightening to continue.
Roof assembly problems continued into early November, when steel support beams for the roof's wheels were found to be bending slightly, a phenomenon known as "sweep." Schuff Steel reported that the sweep in the beams was 13U8 inches, which exceeds the allowable sweep in the design.
Contacted on November 20, Martin/Martin principal engineer Stanley Welton told New Times that additional surveys were needed to determine whether the sweep would have an impact on the roof's performance and if additional repairs are needed.
Since that initial interview, Welton has not returned repeated phone calls seeking additional information.
By late November, designers had developed an extensive procedure to test the roof and adjust wheels that are misaligned with the rails. Those tests began December 4 on the west panel and are continuing.
Despite all the problems encountered during the construction of the stadium roof, Welton, for one, was optimistic that the roof will be operating as planned by opening day.
"I don't think there is any question of that," Welton said.
Time will tell.
