3 ms·
Your articulation is not unique to large diameter tunnels, the generic costs you point to are endemic to any diameter tunnel in America and also to any infrastr
by abduhl 3y ago
Your articulation is not unique to large diameter tunnels, the generic costs you point to are endemic to any diameter tunnel in America and also to any infrastructure project in America that takes place in an urban environment. To say that these things are a "large diameter tunnel" problem is to miss the unique distinctions between TUNNELING costs and INFRASTRUCTURE costs in America. At a high level we agree, but that's not useful for finding a solution to the specific problem of American tunneling costs.
For example, the labor shortage impacts all construction in America but tunnels require even more specialized laborers. Unions drive up the cost of all construction in America, but specific unions (like the Sandhogs) have specific provisions in their contracts that drive up the cost even more. Scope changes impact all construction, but scope changes underground cost orders of magnitude more than surface scope changes (add an offramp above ground versus add an offramp underground). Third party litigation impacts all construction, but the nature of tunneling increases the risk of third party litigation because settlement/sinkholes can occur vast distances away from the work.
- s1artibartfast 3y agoAgain, I think I agree with you on the nature of the problems. Where I disagree is that the boring company is approach minimizes the magnitude and impact of these challenges. For example, if the project scope isn't dictated by politicians, it is less susceptible to political whims and scope changes. If the project scope is smaller, the we all challenges will be fewer. If the tunnels are smaller, service requirements are lower. It would be interesting to know the boring company uses union labor or not.
- abduhl 3y agoThis is 68 miles of tunnel. This is an enormous length of tunnel, its scope is anything but small. I'm not sure what you mean by service requirements for a tunnel, but I assume you mean maintenance. Maintenance requirements for tunnels are only tangentially related to diameter once the final lining is in place, it is mostly driven by length. Realistically there is only so much maintenance that can happen for a tunnel or for any underground structure from the structural perspective since you can't look outside of the tunnel from the inside. So you overdesign. Maintenance requirements thus amount to visual inspections of the inside and maintenance of appurtenant mechanical/electrical systems. These mechanical/electrical systems become more reliable and more efficient with relation to tunnel diameter, and so your maintenance requirements actually decrease on an aggregate basis (i.e. - a tunnel that can support 2 lanes of traffic is less costly to maintain than 2 tunnels that support 1 lane of traffic). And the idea that anything ran by Elon Musk is not susceptible to whims and scope changes is laughable.