A Bridge Too Tough? Antlers Defies Initial Demolition Effort; Final Blast Set for Saturday

The stage was set, a crowd had gathered and cameras were rolling but the Antlers Bridge, after faithfully carrying Interstate 5 travelers across the Sacramento arm of Shasta Lake for three-quarters of a century, declined on Tuesday to take its final bow.

The 1,330-foot-long cantilevered span, which has already been replaced, had been stripped of its deck and rigged with 700 pounds of C4 plastic explosive and was scheduled for a carefully choreographed demolition at 9 a.m.

Sheriff's Department boats patrol the lake prior to demolition.

Sheriff’s Department boats patrol the lake prior to demolition.

As a steady rain fell, the California Highway Patrol stopped traffic on I-5 at both ends of the new bridge and Shasta County Sheriff’s Department boats patrolled the lake to keep any curious onlookers a thousand feet from the blast site.

Project supervisors, contractors, Caltrans workers and officials with Tulsa, Okla.-based Dykon Blasting joined a gaggle of reporters, photographers and umbrella-toting bystanders at the Lakeshore Inn & RV to await the all-clear signal and the countdown to detonation.

Demolition project members gather at Canyon Elementary School in Lakehead prior to the big blast.

Demolition project members gather at Canyon Elementary School in Lakehead prior to the big blast.

The piercing bray of an air horn alerted the audience that the button would be pushed in one minute; it was shortly followed by a Dykon employee barking out a countdown that ended with a throaty “fire in the hole!”

Precautions were taken to keep motorists, boaters and onlookers safe.

Precautions were taken to keep motorists, boaters and onlookers safe.

As advertised, a rapid series of explosions raced across the bridge, north to south, and a loud boom echoed across the lake, followed by a concussive blast of air. Large sections of the green steel trusses shrieked, folded and plunged into Shasta Lake, yet when the smoke cleared, a lengthy section of the superstructure remained in place at the southern end.

Eric Akana, a structural engineer and the Caltrans project manager for the Antlers Bridge project, was initially at a loss to explain how the southern span remained aloft after the detonation. Dykon employees, who are under contract for the demolition and removal of the decommissioned bridge, would have to analyze the situation and determine the safest way to go forward, Akana said.

Smoke clears to reveal the stubborn southern span is still intact.

Smoke clears to reveal the stubborn southern span is still intact.

Four of the five spans laced with explosives collapsed in the demolition. Akana said Dykon workers are prepared to use divers, a barge and a crane to retrieve the trusses and truck them to a salvage yard.

Later on Tuesday, Caltrans spokeswoman Trisha Coder said engineers were able to inspect the remaining span and determined that the pounding rain had compromised the explosive charges. The soggy C4 is being removed and replaced with fresh charges that are now scheduled for detonation on Saturday.

“It will be much less dramatic than today,” Coder said. In the meantime, boating is prohibited on the Sacramento arm of the lake near the bridge and the Antlers boat ramp will remain closed. The CHP will again close I-5 for the Saturday demolition, “hopefully for about 20 minutes,” Coder said.

Traffic on southbound I-5 was restricted to one lane on Tuesday while engineers inspected the rain-dampened charges.

Demolition notes

–Tutor Saliba Corp., the principal bridge contractor, deployed silt curtains to collect any debris from the blast and had workers in skiffs standing by to skim any floating debris.

–The steel superstructure has an undercoating of lead-based primer that is covered by green paint. An analysis by Geocon Consultants indicates dissolved lead levels may reach 1.07 parts-per-billion (PPB). State and federal standards for drinking water allow for a maximum lead level of 15 PPB.

–The demolition project received approvals from the Central Valley Regional Water Quality Control Board, the Environmental Protection Agency and the U.S. Forest Service.

–The concrete piers will be removed at a later date using special wire saws and a crane.

The new bridge

The new Antlers Bridge was a $125 million project that started in 2009 and was expected to take five years to complete. It opened in September. It is 1,942 feet long and 104 feet wide. Designed for a 100-year life, the bridge is composed of 13 million pounds of steel and 36,000 cubic yards of concrete.

An aerial view of both bridges provided by Caltrans.

An aerial view of both bridges provided by Caltrans.

The bridge is supported by massive piers that rise to 120 feet above the lake surface and extend as much as 100 feet to the lake bottom. The piers include 16 bat houses and two large bass motifs (read about the bass art work here).

###

JAN. 12 UPDATE: Caltrans District 2 will temporarily close Interstate 5 in order to allow contractors to demolish the fifth span of the Old Antlers Bridge.

WHEN: Saturday, January 14, 2017 at 8:45 a.m.

WHERE: Lake Shasta, Lakehead

NOTES: There will be no specified media-staging area for this demolition. The California Highway Patrol will hold traffic on I-5 from approximately 8:45 a.m. until 9:15 a.m. The channel under the bridge and the Antlers Boat Ramp will be closed through Sunday. Due to the safety of the public and our workers, the public is asked to not travel to the demolition site during the blast.

Photos and video by Jon Lewis.

Jon Lewis
Jon Lewis is a freelance writer living in Redding. He has more than 30 years experience writing for newspapers and magazines. Contact him at jonpaullewis@gmail.com.
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14 Responses

  1. Jim Gore says:

    I really liked this article, very interesting story and well told!

  2. Well written article, loaded with information!

  3. Beverly Stafford says:

    Who wouldda thought that wet C-4 could be a problem?

  4. R.V. Scheide Jr. says:

    This feels like a metaphor.

  5. A. Jacoby says:

    Thanks, Jon . . . . always like your writing and your coverage. Well done!!

  6. Karen C says:

    Journalism at its best!  Thank you!  Record Searchlight – take note!

  7. Don says:

    Shit happens    —-  o r  doesn’t,   as the case my be

  8. Sally says:

    Thanks dear Jon! Whatever published writings by you are informative and help us who are less knowledgeable learn a significant amount.  We appreciate your efforts!

  9. trek says:

    c4 is water proof

  10. cheyenne says:

    Just proofs they don’t build things like they used too.

    • Steve Towers Steve Towers says:

      Yep.  I don’t want to offend anyone at Caltrans, but the last time I bid on a Caltrans project they selected the lowest bidder of five bidders.

      The highest bidder was a big outlier—a nonprofit from Chico that is clearly used to working off of non-competitive grants.  Twice as expensive as the next three bids.

      Three of us—seasoned environmental contractors—were within the noise of each other on cost—Caltrans could have justified picking any of the three of us based on our relative experience and technical approaches, because our differences on cost were trivial.

      The bid they selected was half the price of the group of three experienced contractors.  I don’t think the guy who prepared that bid lasted another six months with his company.  I also don’t know if Caltrans decided to bail the low-balling firm out with change-orders—it wouldn’t surprise me.

  11. Blaster in Charge says:

    This is a nice case of making sure your contractors have the right licenses for the job. Nobody was licensed to do this blasting…

  12. Joanne Lobeski Snyder says:

    This conversation reminds me of when the contractor hired to build a new bridge across the Trinity River near Douglas City on 299w.  It was discovered that the ratio of cement to sand and water used was on the side of cheap and weak.   I suspect a knowledgeable and ethical person involved in mixing the cement did the right thing when they notified someone about this practice.  Doni might remember if the job was turned over to another company who had to start over again on the bridge.  In another incident several years ago, a citizen overheard some road workers talk about how the contractors were using the wrong sealant on I5 between Lake Head and Mt. Shasta.   She heard one remark that there would be more accidents once it rained or snowed on that part of the road.  She called the sheriff department and was treated like a busybody.  Two days later,  the paper ran an article that contractors had been using the incorrect sealant on the road.   That part of the freeway had to be redone.

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