Why are infrastructure projects not getting cheaper?

I suspect that tighter specifications and higher grade materials has a lot to do with it- back in the day, they pretty much surveyed a road, dug it out, built forms, and poured concrete.

Nowadays, there’s all sorts of stuff like lime stabilization, very specific concrete mixes, and a lot of other things that weren’t in the plans back in the day.

One thing to keep in mind is a certain amount of confirmation bias; the jobs from antiquity that were shoddy or substandard have long since been replaced; it’s only the ones where everything fell into line and there were no major flaws that remain, so it seems to us like the old timers did a good long lasting job for cheap, when in fact, quite a few jobs probably crumbled in a short time, or were found to have major flaws.

Modern roads, etc… will last a LONG time if built correctly, due to the tighter specs and better materials.

In the past there have been problems with counterfeit hardware. The actual tests needed are destructive in most cases, so non-counterfeit hardware only gets tested through sampling. A low, yet significant, defect rate could slip through the testing.
In some extremely critical cases, each piece will be tested by non-destructive means…x-ray, magniflux, etc. Those would be for spacecraft mostly, or certain “jesus bolt” locations on airplanes.

All good responses. The fact is, we are much more environmentally conscious today. You need to file EIS (Environmental Impact statements) and these need to be reviewed.
I often wonder if the Hoover Dam could even be built today-its construction destroyed several ecosystems, and its long term effects have drastically affected water and land use in the Southwest USA.

I would suspect not. At the very least, there would be years of legal wrangling (if not decades of it) by environmentalists and NIMBYists. I don’t think the political will to undertake such a project could be sustained that long.

In this case they came from one small company, and a very high percentage failed. I don’t think they are off the hook.

And they can’t be replaced - what I heard is that they are thinking of wrapping something around them.
On the other hand the Bay Bridge had a large contingency fund, very little of which has been spent, and this fix comes from and is a tiny fraction of it.

BTW, the Governator had something to do with increasing the cost to make the Bay Bridge more beautiful. Maybe back in the days of political bosses things were cheaper because there were fewer arguments. In New York, for the most part Robert Moses built highways wherever he damn well pleased, including across the street from my house. He made people move, but it happened faster.

Actually, I think you have that wrong - it is the current Governor Moonbeam, former Mayor Brown, that faught for the beautification “befitting Oakland”. Ahnold the Governator tried to simplify the design and cut costs but was shot down.

IANA engineer, but isn’t it true that part of the engineering effort is to anticipate unforeseen contingencies and plan accordingly? Yet it seems there’s so often some major problem or obstacle that wasn’t anticipated, and how could it be otherwise? No two infrastructure projects are exactly alike, so there’s bound to be some limitation on how correct the design can be.

This. In Minneapolis, the new bridge carrying Lowry Ave. over the river was just completed last year. The first one lasted about century before having to be replaced. The new one that just opened should, with basic maintenance, last a millennium.