East portal: (Satellite, 445 photos)
This area is enough of a wilderness that there is no nearby town. Unlike West Virginia that has nearby churches, this area has nearby ski resorts.
You can't get an overview image of a tunnel. So here is the east portal. I noticed in a satellite image that there are several of those ventilation ducts on top.
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| Street View, Oct 2021 |
The 1973 Eisenhower and 1979 Johnson tunnels go 1.7 miles (2.7km) under the Continental Divide. When opened in the 1970s, it was the highest vehicular tunnel in the world at 11,112' (3387m). The annual snowfall averages 26' (8m). Of course, Eisenhower was a president. Edwin C. Johnson was the governor and US senator who had actively supported an interstate highway across Colorado. The grade is 1.64% toward the west. But that pales in comparison to the 7% grade on the western approach and 6% on the eastern side. "At the circumference, the tunnel shape varies according to the type of rock encountered, from a straight-leg horseshoe pattern to oval—the latter used where rock stress is greatest. Maximum excavated height for the tunnels is 48 feet, with a width of 40 feet. However, when driving through the tunnels, the actual height is not apparent. The exhaust and supply air ducts are above a suspended porcelain enamel panel ceiling, and a drainage system is provided underneath the roadway surface." [codot] Given grades of 6% and 7%, I used a satellite map to determine if they had a third lane for trucks using really low gears. To my surprise, the west side has three lanes, but the east side has only two. I would expect it to by symmetrical since both sides have the same traffic density.
Before they built I-70 through the Continental Divide, one had to take US-6 over Loveland Pass. Note how twisty that 2-lane road is.
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| Satellite |
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| Colorado Department of Transportation posted Construction of the Eisenhower Tunnel! This year we continue to celebrate 50 years of the Eisenhower Tunnel, which opened to traffic in 1973. Tunnel planning and construction spanned four decades, starting in 1932. The geology of the tunnel was a challenge for construction, and one of the project's resident engineers even described it saying, "We have two kinds of rock: bad and very bad." The issues with the geology of the tunnel ended up adding a considerable amount of time to the construction timeline. Over the five year period of construction of the Eisenhower bore, 6,000 people worked a total of approximately 4.9 million hours. Construction of the tunnel was monumental for the time, and is still considered an impressive engineering feat by today's standards. Thanks to the hard work and dedication from everyone involved, Colorado now boasts the highest tunnel in the US Interstate system! |
"Construction faced a number of setbacks, including delays and high costs. It was the costliest federally-funded project at the time, with a price tag of $108 million (amounting to $622 million in 2020). A fault line was discovered on the tunnel site, requiring engineers to take emergency measures to prevent cave-ins while workers were in tunnels. Unfortunately, these measures were not enough and three workers were killed during the first tube’s boring and another four during the second tube’s." [UncoverColorado]
"Among the project’s large workforce, Janet Bonnema deserves special attention. The Colorado Highway Department mistakenly hired her, a highway engineer with a degree from the University of Colorado, because they believed they were hiring a well-qualified “Mr. Bonnema.” When Bonnema arrived on the job, she was not allowed to enter the tunnels, even though it was her job to do so as an engineering technician. She was kept outside the tunnels and at a desk because construction workers believed having a woman in the tunnels would jinx the worksite. The taboo was so widely believed that on the day Bonnema finally entered the tunnels – surrounded by reporters, many of them also women– most of the work crew walked out of the tunnel, some of whom never returned to the job. The majority of the crew, however, returned to work the next day, and Bonnema continued to work in the tunnels, often dressed in loosely fitting coveralls so no one could tell her identity." The tunnel cut the travel time across the divide from more than an hour to 5 minutes. The cost was $257m. [ColoradoEncyclopedia] (Update: the $108m figure was for the first bore. The $257m figure is for both bores. "It cost about $116.9 million to build the westbound bore and $144.9 million to build the eastbound bore" [40-facts])
Here is a good view of the ventilation ducts. Keeping the level of carbon monoxide low enough is a major issue.
"To power the tunnel, expenses are about $70,000 per month." [40-facts]
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| Colorado Department of Transportation posted |
The fhwa provides Mz Bonnema qualifications for the job. The walkout of 70-100 workmen cost about $10,000. But fhwa doesn't mention that the problem as solved by wearing coveralls.
A timeline and an album that includes several construction photos.
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