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Why Utah is digging up a $2.4bn mega-temple

Fred Mills doesn't just report on a construction project; he reveals a high-stakes gamble where a $2.4 billion retrofit serves as a proxy for a city's entire identity. While most coverage of the Salt Lake City Temple focuses on its religious significance, Mills argues that the engineering feat required to save it exposes a rare moment of preservation in a city that has historically shrugged off its own history. This is not merely a story about stopping a building from falling over; it is a narrative about how a 19th-century experiment in urban planning is finally being forced to confront the seismic reality of the 21st century.

The Seismic Imperative

Mills immediately grounds the reader in the terrifying math of geology, noting that the Wasatch Fault runs directly beneath the valley. He writes, "A major earthquake of around magnitude 7 happens once in a millennia. That may sound like a lot of time, but the reality is there's a 57% probability of at least one earthquake of magnitude 6 or greater in the next 50 years." This statistic is the engine of the entire piece, transforming a routine maintenance issue into an existential threat. The author effectively uses the 1994 Los Angeles earthquake and the 2003 Iran disaster as benchmarks to illustrate the potential devastation, making the abstract threat of a "magnitude 6" quake feel viscerally real.

Why Utah is digging up a $2.4bn mega-temple

The coverage draws a compelling parallel to New Zealand's Christchurch Cathedral, where a similar magnitude 6.3 quake led to the destruction of a historic landmark. Mills observes, "In many ways, the Church of Latter-day Saints is trying to do exactly the same thing before disaster strikes." This comparison is crucial because it shifts the narrative from prevention to urgent necessity. Critics might note that the comparison to Christchurch is slightly imperfect, as the Utah temple is a fortress of granite while the cathedral was largely unreinforced masonry, but the structural vulnerability remains the same.

The plan to keep it standing is a remarkable U-turn from a city that's normally shrugged off its historic buildings.

Engineering the Impossible

The technical core of Mills' argument lies in the description of "base isolation," a process that sounds almost magical in its simplicity. He explains that the team is "decoupling the structure from any ground motion" to allow the building to move independently. The scale of this operation is staggering, with Mills detailing how they excavated 10.6 meters deep to install 98 massive isolators, each weighing 8,000 kilos. He writes, "Try and think of it like a raft made of concrete-filled steel pipes bored underneath the building structure." This analogy is a masterclass in simplifying complex engineering for a general audience, turning a technical specification into a mental image of a floating fortress.

The sheer physical effort required to retrofit a 19th-century stone structure without damaging it is emphasized through the description of the underpinning process. Mills notes that the team used "micro piles, secant piles, tieback anchors, tensioned tie rods, hand-constructed underpinning piers, plus consolidation grouting" to support the heavy stone walls while digging underneath. This level of detail serves a dual purpose: it highlights the difficulty of the task and underscores the immense value the Church places on the building. The argument here is that the cost is justified not just by the building's size, but by the impossibility of replicating its craftsmanship.

The Urban DNA of Salt Lake City

Perhaps the most distinctive part of Mills' coverage is the deep dive into the city's unique grid system, which he argues was engineered for a different era. He points out that "Salt Lake City isn't just another American grid. It's one of the most deliberately planned urban layouts in the world." The author contrasts the massive 200-by-200-meter blocks of Salt Lake City with the standard 80-by-200-meter blocks of New York, explaining that these "micro farms" allowed for a hybrid rural-urban lifestyle. This historical context is essential because it explains why the temple dominates the skyline; it was the anchor of a city designed around the idea of self-sufficiency.

Mills writes, "The temple really did become the anchor points of Salt Lake City's urban plan. Streets, public squares, and civic institutions aligned themselves around the temple block." This framing elevates the temple from a religious site to a civic linchpin. The author suggests that the wide streets, originally designed for ox teams, inadvertently saved the city from the gridlock that plagues other American metropolises, allowing for easier adaptation to cars and light rail. However, this success has come at a cost. Mills admits that "Skyrocketing land values and pressure from developers has meant the destruction of many heritage buildings," making the $2.4 billion investment in the temple a symbolic stand against the erasure of the city's past.

This building's going to go from being in danger of collapse in an earthquake to becoming one of the most seismically resilient historic structures in the world.

Bottom Line

Fred Mills' strongest asset is his ability to weave together geology, engineering, and urban history into a single, cohesive narrative about resilience. The piece's greatest vulnerability is its reliance on the assumption that the temple's survival will indeed catalyze a broader preservation movement in a city that has historically favored development over heritage. Yet, the sheer scale of the engineering feat described leaves little doubt that this project is a watershed moment for Salt Lake City, proving that even the most stubborn historic structures can be saved if the will and the resources align.

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Why Utah is digging up a $2.4bn mega-temple

by Fred Mills · The B1M · Watch video

>> This is the largest Mormon temple in the world. You might recognize it from a few notorious reality shows. >> Don't drink, don't swear, treat your body like a temple. It is so hard to be a good Mormon.

That's right. This is the Church of Jesus Christ of Latter-day Saints. It's being dug up. Well, its foundations are, all in a bid to stop it from falling over.

And this retrofit project is going to cost an estimated 2 billion US dollars. But more than that, the temple exemplifies the hidden architecture of one of America's strangest and most fascinating cities. The plan to keep it standing is a remarkable U-turn from a city that's normally shrugged off its historic buildings. This is the 2 billion-dollar operation to save the world's largest Mormon church and the secret history that allowed it to exist in the first place.

Now, the first thing you should know about the Salt Lake City Temple is that it's very old and very big. It utterly dominates the Salt Lake City skyline and that's no accident. The temple took more than 40 years to construct and was completed over 130 years ago. It was built from granite and quartz monzonite mined from Little Cottonwood Canyon.

It features walls up to 9 ft thick, contains 170 rooms, and sits on an 11.4 acre site. It is a hefty building. But while it was built for many things, including weddings and ordinances, it was not built withstand earthquakes. And that's actually a very big problem.

The Wasatch Fault runs along Salt Lake Valley and geologists estimate that a major earthquake of around magnitude 7 happens once in a millennia. That may sound like a lot of time, but the reality is there's a 57% probability of at least one earthquake of magnitude 6 or greater in the next 50 years. To give you an idea of how devastating that could be, it would be around the same size as the 1994 LA earthquake that forever changed the building codes in the US. Or the 2003 Iran earthquake that killed 26,000 people.

Aside from massive quakes, there are still plenty of larger ones, magnitude 4 and above, that happen around four to five times a year within 300 km of Salt Lake City. A magnitude 6 quake would be likely to cause significant damage to the temple ...