Ever since major news outlets like CNN and the Washington Post began reporting on the logistics of a proposed border wall between the United States and Mexico earlier this year, precast concrete has been the material of choice. Now, a recent New York Times piece has furthered that discussion and once again thrust precast into the spotlight.
Photo courtesy of Chris Boswell | Dreamstime.com.
While presidential campaigns generate an endless stream of news, it’s improbable for a building material to be a focal point of the coverage. But the most talked about candidate in the race has proposed a nearly 2,000-mile wall – later scaled back to 1,000 thanks to existing natural barriers – along the border between the U.S. and Mexico. And the conclusion of experts contacted by the media is that precast concrete is the best material for the job.
There are many factors to take into consideration such as time, capacity, cost, labor, land, environmental concerns and long-term maintenance. There’s also the fact that the candidate proposing the wall first has to win the presidential election and then marshal Congress into supporting it. But one factor that does not require any consideration is the industry that could accomplish the feat: the precast concrete industry. So just what it would take for the precast industry to complete a project like this?
Both CNN and the Washington Post cited the contemplations of a structural engineer who analyzed the challenge for The National Memo. He first notes that only one larger wall has ever been constructed and only through the dangerous and sometimes forced labor of millions of Chinese throughout hundreds of years. Technology has obviously changed, but the point is there’s no basis for comparison. This is why getting the details down is kind of like nailing Jell-O to a tree – variables and opinions lead to countless conclusions. In this analysis, like any other, assumptions abound.
The engineer dismisses various methods such as concrete masonry units due to the labor required and cast-in-place concrete for issues regarding proper curing in the desert heat. That leaves precast concrete, with its strength, consistency, quality control and on-demand delivery, as the material of choice.
The major challenge posed for the precast concrete industry would be capacity. This includes the number of facilities, max output and labor. The best estimates of the North American precast concrete industry based on NPCA’s benchmarking survey and third-party sources place it somewhere in the $15-$20 billion range per year. The Trump campaign puts the cost of the wall at $8 billion. The Washington Post, citing a retired estimator and economist for a large construction firm, placed the cost of the precast alone at $10 billion. And the New York Times reported the wall would cost more than $25 billion. So even spread over four years, the wall would require a major expansion of the precast concrete industry.
Challenges like this are where the precast industry shines. New plants would spring up around the border and existing plants would ramp up production. The engineer whose numbers are cited by the major news outlets proposes an eight-inch-thick, 25-foot-tall wall with five feet below grade. By his estimation, that’s 339 million cubic feet or nearly 12.6 million cubic yards of concrete. Even cut in half for the 1,000-mile version, that’s a lot of precast concrete wall panels. It would be a public works project that dwarfs the Hoover Dam – a longtime standard for scale. But the precast concrete industry could make it happen.
Could this wall be built? Of course. Would precast concrete be the right material for the job? Absolutely. When it comes to speed, strength, quality and durability, nothing trumps precast concrete.
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