The crossing of the largest wildlife in the world is taking shape on the occupied road 101 in Agoura Hills, about 35 kilometers north -west of Los Angeles. Phase 1 of the Wallis Annenberg’s wildlife crossing
It is almost complete and phase 2 started this summer.
Public-private collaboration of $ 92 million is led by the California Transport Owner (Caltrans), with the National Wildlife Federation, which serves as a key partner in fund collection. Rock Design Associates LLC, based in Chicago, is the leading design and Valencia, Ca Rasmussen Inc., based in California, is the general contractor.
The purpose of the 12 -hectare project is to protect and reconnect native animals isolated by the road. A study of the Service of the National Park found that the roads are not only mortal for the animals that try to cross, but also create habitat islands that can genetically insulate wildlife as the pumars of the mountains of Santa Monica, as well as the bobbins, the birds and the lizards and other wildlife.
“The crossing of Wallis Annenberg’s wildlife will soon protect the Los Angeles native wildlife and more than 300,000 drivers daily, as well as an avant -garde model for the conservation of urban wildlife,” said Gavin Newsom California governor in a statement.
In phase 1, the crews built the 210 feet in length, 174 feet wide, providing a vegetative space surface up to 4 feet of soil and 5,000 plants originating from the Santa Monica mountains, that is, species of the coastal sage rubble plant. It is built with more than 26 million LB of concrete, vegetable sound barriers, habitat rocks formations and 6,000 Cu YDs of soil.
Robert Rock, president and CEO of Rock Design Associates, says that the biggest difference between the crossing of wildlife and a regular road bridge is that crews are treated with dead load instead of living load. “You have to deal with the load at the top of the structure and soils and the saturated water,” says Rock. He adds that the weight of the dead load design was about 425 lb per ft above the structure.
Darwin Vargas, a senior chair engineer, says that the purpose of the junction, to provide animals, is unique. “We usually build bridges to allow the movement of trains, vehicles, cyclists or pedestrians. This bridge is built for nature and to allow animals to be crossed,” says Vargas. “What is unique is the approach we adopted on how to design and build it. As an example, the color of concrete on the bridge and lighting was specifically chosen to minimize the impact of wildlife, while maintaining the standards of safety for the traveling audience. The soil that was placed on the bridge was designed from the molecular level.”
Graphic courtesy of the Annenberg Foundation
The junction is a nailed bridge, supported with 82 prefabricated box beams weighing 60 tons each. Adam Rasmussen, President of Ca Rasmussen, says that for a nailed bridge, the roof is what keeps her united.
“You have a buttress on either side of the 101 motorway and hang in the air,” says Rasmussen. “You put the beams and connect as a Lego set and the concrete keeps it all together.”
“The beams combine like a giant bar of three musketeers.”
—Robert Rock, President and CEO, Rock Design Associates
As part of phase 1, the crews refill the north side of the crossing. For phase 2, the south side of the crossing will be filled with an equal amount of land for weight and pressure.
“Caltrans is very specific that when pressing against one side of the bridge, they want you to bring this dirt to the other side of the bridge, because this will keep it together,” says Rasmussen.
The beams were combined “as a three -bar giant,” says Rock. “There is a giant foam piece inside, and there is a cage to receive, and then they had to put concrete outside,” he says.
“You could think you could pour [concrete] On both sides, and it would be fine, “he adds. So what they had to do was pour it on the one hand, vibrate it below the bottom, then pour it to the other side and bake the top to close the whole thing.”
The first step of construction, the crossing of wildlife was to build concrete foothills on both sides of the US 101.
Photo courtesy of caltrans
The designers chose soon for the casting beams on the site. The crews were able to walk between three and four of the units each night, requiring only half of the motorway that closed at once. “If we had done concrete on the site, we would have had to build all the false work and close the entire motorway,” says Rock, adding that it took 43 consecutive nights of alternative night closures to place the 82 beams.
Vargas says that the most difficult aspect of the project was to close the 101 motorway as the crews erected the beams with the help of a 500 tonnes crane.
“We couldn’t divert from the tolerance of being a half-inch in the beams more than 100 feet in length to put them in place,” he says, noting that the placement of the beam took only six weeks to two months.
Rasmussen claims that he established the false work to support these beams. “We used more than 100,000 feet of wooden board and 11,000 three -quarters of an inch,” he says. “This was a design created by Rasmussen in collaboration with Calerans to ensure that temporary supports could support the beams until the upper concrete roof was poured.”
The occupied motorway had to be closed for periods while a 500 tonne crane placed the prefabricated beams for the passage.
Photo courtesy of caltrans
Creature’s cross
Phase 2 will again connect the mountain to the north of the motorway with the South Desert area, allowing animals to go free and safely through the structure. This will involve approximately 11,000 truck loads that move more than 110,000 C of land in a differential of 125 feet.
“Most of the dirt is on the north side of the motorway and is needed on the south side to complete the phase 1 link to phase 2 of the project,” says Rasmussen. “There is an incredible amount of finish classification to be completed. The final notes are very important for the project, as they are part of a meticulous landscape design that will be planted and can be gardening to mix in the existing mountains.”
Rasmussen adds that the crews are trying to reuse as many existing land as possible to the site, which would reduce the price.
“Each time you do not have to handle the dirt or transport it, save money, so we try to rebalance the place, adjust the notes and we are mining the dirt to see if it can be analyzed and processed -something to use it to refill structural,” he says. “Obviously, when you are building bridges and put them in the air, you must refill -you against the buttresses; you cannot use any dirt, it must be selected and it must have special characteristics. And this is a great piece of the project, probably millions of dollars.”
“This bridge is built for nature and to allow animals to believe.”
—Darwin Vegas, Senior Bridge Engineer, Hotrans
For phase 2, the Earth will be used to refill the south side of the wildlife crossing, and a new 60 -foot bridge will be built by 60 feet wide on Agoura Road. This new structure will be a bridge nailed to the crossing of the largest wildlife, but it will not have prefabricated flags.
Phase 2 also involves the restoration of natural hydrology to ensure proper water flow, ripe heritage protection and coordination with multiple agencies to transfer the essential uses to the motorway corridor.
The project was originally planned to open in 2025, but the “last two sources caused rainstorms, which had a significant impact on promoting the calendar again,” says Rock. He says that on a couple of occasions, heavy non -reasonable storms caused several inches of rain, which washed too many amounts of sludge on foot while crews tried to complete the motorway counterposes. This caused significant delays in the calendar, says Rock.
Once the bridge roof was completed, 6,000 cenes were distributed to create a natural environment.
Photo courtesy of caltrans
When everything is completed in December 2026, the project will be mixed in the mountains with the use of colored concrete instead of painting on the two bridges and all the exposed elements, including columns, buttresses and exterior beams.
“The concrete of colors makes this bridge a bit different and adds its beauty, but it is also difficult,” says Rasmussen. He says that the color was so rich and that there was so much additive in the mixture to achieve the color they wanted, that the concrete was slow to heal and obtain the strength he needed.
“It was a matter of seeing concrete care for 28 days, but it was cured in time, and everything worked at the end,” says Rasmussen. “And the slower the concrete is cured, the less possibility there is to crack -“
Rock says that to obtain the desired brown color, the crews added about 55 lb of pigment to each concrete mix, unlike about 5 or 6 lb per mixture for the architectural concrete.
“We have added a pigment to the concrete to reduce the concrete’s superficial reflectivity index so that when artificial light bounces this surface and hits this particle in the atmosphere, we have no glow from the sky, because Sky Glow is really an impediment to the movement of wildlife at night,” says Rock.
The project exemplifies an increasing trend thanks to $ 350 million in Investment Financing in Infrastructure and jobs for the construction of wildlife that develops in 2023. A proposed high -speed railway line that connects southern California and Las Vegas will include the cross -life crossings as part of an agreement between the developer, Brightline West and the Fish Department of Fish and Fish Department. California.
And in Colorado, a dollars of $ 15 million from Groenly Wildlife aims to reduce up to 90% of the collisions of vehicles-animal vehicles in one of the busiest sections in the state. The 209 -foot bridge, 200 feet wide, will rival, when built, Annenberg Crossing for the state of being the largest in the world.
