Tunnel vs Bridge

SCANALYZER The Happening World
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I know this will annoy some Scanalysts who are living in the past, when the US could build giant civil engineering works like the Hoover Dam and the Empire State Building. But that was before we were all born. So let’s look at the world we live in today.

The Francis Scott Key Bridge in Baltimore was damaged in an accident and collapsed in March 2024. Since then, there has been lots of paperwork, and presumably lots of attorney billable hours, but no bridge. The current plan is to build a new bridge by 2030 – 6 years, assuming that schedule is more achievable than the one for California’s High Speed Rail project.

Meanwhile, somewhere else, a record-breaking 50 foot diameter tunnel has been drilled for 9 miles through solid rock under one of the world’s largest rivers … in only 2 years. I, for one, regret that the US which used to lead the world in physical accomplishments now leads the world only in the volume of regulations.

World’s largest-diameter high-speed-rail shield tunneling machine ‘Linghang’ reaches Taicang - Global Times

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I recall some old Soviet propaganda (likely accurate in this particular case). It showed a photo or drawing (I don’t recall which) of a railroad train consisting of 20 or so open top bathtub gondola (coal) cars, but filled with stacks of paper. The caption described paper as by far the greatest output of Washington DC. I guess now it is electrons and ‘holes’ in silicon, but far greater in magnitude and deleterious effect. Sadly, your observation is emblematic of all bureaucratic/technocratic Western Civilization. What a shameful waste of potential. I guess that’s an unavoidable consequence of a hyper-regulatory state where political considerations trump merit and actual production. Similarly, finance has swallowed economics. Collapse of both systems are pending.

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Oh well! Looks like that far-off 2030 date for reopening the bridge is going to slide. Maryland has rejected the cost estimate developed by the Phase 1 contractor doing the design work.

Some State punter estimated the new bridge would cost $4,300,000,000 to $5,200,000,000. Do they have any idea about how much work a contractor has to do to come up with a realistic cost estimate for a project in the $Billion range? The detailed design; the Material Take Off; the labor hours; constraints on availability of materials and skilled labor; scheduling; compliance costs; contingencies; etc. It takes thousands of hours and millions of dollars to build a realistic cost estimate of this magnitude.

Apparently, the contractor who did the actual cost estimating effort came up with a higher number than the State had pulled out of the air. (When was the last time the State of Maryland built a big bridge?) State & contractor have now parted company, and the schedule has surely slipped.

China’s many current infrastructure successes, and the US’s own amazing construction history, prove that it does not need to be this way. We are choosing mediocrity – or allowing politicians & lawyers to chose it for us.

Maryland to part ways with Key Bridge contractor after disagreement on cost - The Washington Post

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Yeah. The “adversarial truth finding process” is certainly the best way to design a bridge (or anything for that matter). A jury is the best instrument to “settle the science”.

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Things are unfortunately a bit slow on Scanalyst these days – perhaps a topic for another discussion. In the meantime, let me share another datapoint on the progress in tunneling technology on the other side of the world.

It seems that a lot of the driver comes from construction of the High Speed Rail system. (Note for California readers – “construction” refers to the cheap phase of a project involving actually moving dirt after all the expensive legal phases have been completed). As Newton explained all those years ago, a massive object travelling at high speed tends to keep on travelling in a straight line – which is a real constraint on high speed rail lines.

This ends up with China digging lots of tunnels in difficult conditions, dealing with high pressures and other problems. Here is an innovative approach – the kind of thing at which the pre-lawerly US used to excel:

"Replacing cutters under such extreme pressure is widely regarded as one of the toughest challenges in shield tunneling, the company said.

Traditional compressed-air methods allow only about 40 minutes of effective work per person per day and are limited to depths of around 60 meters. To overcome this, the construction team spent three years adapting deep-sea saturation diving technology.

They developed China’s first domestically built saturation hyperbaric system for shield tunneling - nicknamed the “Deep-Sea Space Station,” Dong Bing, chief mechanical engineer of Jintang tunnel project at the company, was quoted as saying.

“The system includes living, transfer and control modules, all designed and manufactured in China. It can house nine workers for extended periods. Crew members travel to the work face in a transfer chamber and can operate for up to eight hours at a stretch, enabling 24-hour multi-shift work for as long as 28 days. After the job is finished, workers undergo a single controlled decompression, greatly reducing health risks from repeated pressure changes,” said Dong."

World’s longest undersea high-speed rail tunnel completes high-pressure shield cutter replacement in E.China - Global Times

Inquiring minds might wonder what military applications might be possible with such advances in digging deep.

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