NDOT Post-Earthquake Statement for Las Vegas

Official Statement from NDOT released 3:45 pm 5/22/2015:

A shallow 5.4-magnitude earthquake occurred at 11:47 a.m., May 22, over 100 miles north of Las Vegas. However, its impact was felt in the Las Vegas valley. The temblor occurred at a depth of 3.7 miles, the U.S. Geological Service said, with subsequent quakes of magnitudes 3.8 and 3.0 occurring minutes afterward.

The temblor consequently caused the rubber encasing the bridge seam on U.S. 95 southbound to the Interstate-15 southbound ramp to separate, prompting an immediate shutdown. Engineers inspected supporting bridge columns and beam pins to ensure the bridge’s structural integrity. The Martin Luther King onramp to southbound I-15 and U.S. 95 southbound to I-15 northbound ramps were also closed as a safety precaution.

“The joint damage was pre-existing. The tremblor simply dislodged the protective rubber encasing the bridge seam making it look much worse than it was in reality,” said NDOT District I Engineer Mary Martini. “However, we’re issuing an emergency contract to repair the seam. Meanwhile, the ramps remain structurally sound and safe for travel.”

The cast-in-place concrete and steel reinforced ramps will reopen within the hour. And they will remain open throughout the holiday weekend.

“The ramps make-up the I-15/U.S. 95 interchange that sees 250,000 vehicles daily, making it the busiest stretch of roadway in the state with 25,000 lane changes an hour,” said NDOT spokesman Tony Illia. “However, those numbers are considerable higher during Memorial Day with another 198,000 anticipated drivers coming to Las Vegas over the long holiday weekend.”

NDOT inspects its 1,100 bridges statewide at least twice a year. Its bridge structures are designed to withstand rigorous wind and earthquake loading. Nevada lies within an active seismic zone, which is something that is taken into account during project design and engineering. Nevada consequently has some of the best rated bridges in the country, according to a recent report by the American Road and Transportation Builders Association (ARTBA). Only 1.8 percent of Nevada bridges are classified as structurally deficient, which is the lowest in the country. The national average is six percent. (Here’s a link to the study: http://bit.ly/1F4ZLVH).