pcloudy.png
Wednesday July 17th, 2019 1:04PM

New California bridge gets sensors to gather earthquake data

By The Associated Press
Related Articles
  Contact Editor

LONG BEACH, Calif. (AP) — A replacement bridge under construction at the second-busiest port in the U.S. isn't just a crucial route for cargo trucks and Southern California commuters — it's a concrete-and-steel science experiment for engineers and seismologists.

The new bridge, which will stretch 8,800 feet (2,680 meters) over the Port of Long Beach, is being built with about 75 seismic sensors that will measure the forces imparted on the span when one of several nearby faults set off an earthquake. It will replace the Gerald Desmond Bridge, though it's unclear if it will retain that name.

The new bridge is due to open next year.

"New bridges don't come along very often, so it's exciting," said Dr. John Parrish, head of the California Geological Survey. His agency's Strong Motion Instrumentation Program will be among those crunching the information the sensors capture. The data will be added to the state's database of earthquake knowledge.

California's bridges and other infrastructure have been outfitted with quake sensors called accelerometers since the 1970s. The eastern span replacement of the San Francisco-Oakland Bay Bridge that opened in 2013 has more than 200.

But the building of the new Long Beach span, south of Los Angeles, marks the first time the sensors have been incorporated into the design of a California bridge from Day One, said Duane L. Kenagy, an engineer and the port's interim deputy executive director.

The original bridge has taken a "pretty good beating" since it was built in 1968, Kenagy said. Evidence of that is the netting — called "diapers" — recently placed underneath to capture hunks of concrete that regularly break away. The roadway is "reaching the end of its natural life" but is considered safe for traffic until the new bridge opens, he said.

About 15 percent of all containerized cargo entering the U.S. travels over the span daily, and it's a key artery for motorists traveling between the city of Long Beach and San Pedro, a working-class waterfront neighborhood on the southern edge of Los Angeles.

Its nearly $1.5 billion replacement is historic for the built-in seismology and because it's the first cable-stayed vehicle bridge in California. Cable-stayed bridges are distinct from more common suspension bridges in that the main span deck is entirely supported by cables connected to the twin 515-foot (157-meter) towers. It makes for a particularly sturdy design that's been tested to withstand powerful earthquakes or a terrorist bombing.

"You just can't knock one of these things down by knocking out one or two cables," Parrish said. The design, popular in Asia and parts of Europe, is catching on in the U.S. as larger construction machinery and new high-tech materials make them cheaper and easier to build.

Designed to last 100 years, the new bridge has a higher clearance for larger cargo ships and elastic "points of isolation" that enable segments to move independently without damaging other sections. Joints and bearings are designed to break under stress and are easily replaceable to get the bridge reopened quickly after a violent shaking shuts it down.

The old bridge will be torn down. It had no sensors, so seismologists and engineers are eager for the information the new span will provide.

The span is just a few miles from two active faults — Newport-Inglewood and Palos Verdes — capable of quakes in the range of magnitude 6.5 to 7. A magnitude 6.4 quake along the nearby Newport-Inglewood fault leveled Long Beach in 1933. And a mega-fault, the infamous San Andreas, is only about 50 miles (80 kilometers) away at its closest point.

Data recorded by the sensors — a quake's magnitude along with how fast the ground is moving and at what trajectory it hits the bridge — are sent via the state's Integrated Seismic Network to scientists at state offices in Sacramento as well as the University of California, Berkeley and Pasadena's California Institute of Technology.

___

Follow Weber at https://twitter.com/WeberCM

  • Associated Categories: U.S. News, Associated Press (AP), AP National News, Top U.S. News short headlines, AP Business, AP Technology News
© Copyright 2019 AccessWDUN.com
All rights reserved. This material may not be published, broadcast, rewritten, or redistributed without permission.
Strong typhoon slams western Japan; 2 dead, airport flooded
A powerful typhoon has slammed into western Japan, disrupting land and air travel and leaving at least two people dead
9:36AM ( 9 minutes ago )
Kerry Perry quits as president of scandal-hit USA Gymnastics
Kerry Perry quits as president of scandal-hit USA Gymnastics, which loses faith in her leadership
9:33AM ( 13 minutes ago )
New California bridge gets sensors to gather earthquake data
A replacement bridge under construction at the nation's second-busiest port isn't just a crucial route for cargo trucks and Southern California commuters _ it's a concrete-and-steel science experiment for engineers and seismologists
9:32AM ( 14 minutes ago )
Associated Press (AP)
Major UK union backs calls for new Brexit referendum
One of Britain's biggest trade unions is backing calls for a new public vote on leaving the European Union, saying voters were misled during the 2016 referendum campaign
8:32AM ( 1 hour ago )
World stocks mixed on worries over trade, manufacturing data
World stocks are mostly down on worries over trade, manufacturing data
8:13AM ( 1 hour ago )
China's Xi to send top ally to North Korea anniversary
Chinese President Xi Jinping is sending a top political ally to attend celebrations of the 70th anniversary of North Korea's founding this weekend
8:02AM ( 1 hour ago )
AP Business
Sensors on new California bridge to record earthquake data
A replacement bridge under construction at the nation's second-busiest port isn't just a crucial route for cargo trucks and Southern California commuters _ it's a concrete-and-steel science experiment for engineers and seismologists
2:01AM ( 7 hours ago )
London show explores hidden world of facial recognition
A new exhibit in London explores how computers' ability to read faces is changing the world, in ways that aren't fully understood
1:05PM ( 20 hours ago )
Facebook adds Alaska's Inupiaq as language option
An Inupiat Eskimo language option is now available on Facebook, thanks to Alaskans who made it a reality through the social media giant's community translation tool
2:37PM ( 1 day ago )
AP Technology News
Strong typhoon slams western Japan; 2 dead, airport flooded
A powerful typhoon has slammed into western Japan, disrupting land and air travel and leaving at least two people dead
9:36AM ( 9 minutes ago )
Kerry Perry quits as president of scandal-hit USA Gymnastics
Kerry Perry quits as president of scandal-hit USA Gymnastics, which loses faith in her leadership
9:33AM ( 13 minutes ago )
New California bridge getting sensors to measure earthquakes
A replacement bridge under construction at the nation's second-busiest port isn't just a crucial route for cargo trucks and Southern California commuters _ it's a concrete-and-steel science experiment for engineers and seismologists
9:27AM ( 18 minutes ago )
Kavanaugh pledges to be 'team player' on Supreme Court
Supreme Court nominee Brett Kavanaugh is promising to be a team player if confirmed to the closely divided court, declaring that he will be a "pro-law judge" who won't decide cases based on his personal views
9:02AM ( 44 minutes ago )
Trump says Sessions' DOJ has placed GOP in midterm jeopardy
Trump tweets that federal indictments against two Republican congressmen placed the GOP in midterm election jeopardy
8:56AM ( 49 minutes ago )