Thursday, Aug. 20, 1998 | 11:24 a.m.
Uneven settling of the $950 million Mandalay Bay hotel-casino on the Las Vegas Strip appears to have been halted, a Clark County building inspector said.
"It's been holding very steady for the past 30 days," said Ron Lynn, a supervisor with the county's building-inspections division. "There's been no significant movement at all."
The massive Circus Circus Enterprises Inc. project under construction south of Luxor has settled unevenly as its weight squeezed moisture out of an underlying aquifer.
Settling is normal for buildings erected here, but the core of the 43-story, 3,700-room hotel-casino has sunk slightly more than 17 inches, while one wing has settled 8 to 9 inches and the other about 2.
As a result, Circus Circus retained a Pennsylvania company that specializes in correcting the problems. Nicholson Contruction Co. is installing 536 "pin piles" about four feet apart under the building to stabilize the structure.
Pin piles are metal cylinders up to eight inches wide that are filled and surrounded with high-pressure grouting to support sagging portions of the building.
The pin piles are inserted into holes drilled through a steel and concrete mat that allows structures built on complex soils to "float," minimizing settling problems.
Tests on the pin piles being installed at Mandalay Bay show they are capable of supporting up to 600,000 pounds of pressure per square inch before failing.
"The stabilization has corresponded with the installation of the initial 126 pin piles, 40 of which have been load tested," Lynn. "More than 200 holes have been drilled through the concrete mat foundation so far.
"The settlement has been holding steady in the mid-17-inch range in the core, while there's been about another inch of settling in the middle of the north wing, which had previously settled about 5 inches," he said.
"The north wing is well within the tolerance levels expected in the original design."
Circus stock, which fell sharply following the collapse of merger talks with Hilton Hotels Corp. earlier this year, has sunk further in the midst of wild rumors about the magnitude of the settling.
Lynn said Circus is proceeding with plans to install all 536 pin piles even though the settling appears to have been stabilized.
"The additional piles should mitigate any potential for long-term settling and represent an enhanced safety factor," Lynn said.
"Both the county and Circus like the conservative approach in this case. And Circus is being even more conservative than required by the building codes."
Lynn said he didn't know what the stabilization would cost, and Circus' chief spokeswoman couldn't be reached for comment.
A month ago, company sources estimated the cost at $4 million to $8 million. Later, Circus filed a report with the Securities & Exchange Commission saying the stabilization wouldn't "materially increase" construction costs at the project.
Mandalay Bay is still on schedule for a spring 1999 opening, the filing said.