How do you build a road?

December 15, 2006 7:33 AM

Why does road construction take so long?

It seems that there is always a road around here being re-paved, built, etc. This is a natural part of living in a growing city. I've noticed some projects take years--we have two multi-year projects going in my city right now. Roadbuilders: what is the process, and why does it often so lengthy?

posted by frykitty to travel & transportation (16 comments total)

While not an extreme work, I would like to point out how awesome a project can go with good management.

Case in point: Langdon Street Bridge, Montpelier, VT.

Now the FIRST thing that amazed me was that the town put up an entire website detailing this project.

The second thing was the timeline that they actually met! 100%.

They also have the closure plan, the design plan, and EXACTLY why they needed to do this project.

Amazingly well done.
posted by SirStan at 7:43 AM on December 15, 2006

Well, one issue is that there generally isn't the political will to shut down a portion of a major road entirely during the construction, so they have to close down and work on lanes individually.

If you can shut down a section of road entirely, it can go much faster. Hyperfix 65/70 completely shut down a section of I-65/I-70 in downtown Indianapolis about a mile long in 2003. The construction was completed in under three months. The downside, of course, is that you had a major, heavily travelled interstate entirely closed off, so traffic had to detour onto surface streets to bypass the construction.
posted by DevilsAdvocate at 7:52 AM on December 15, 2006

Additionally, if you are completing some parts on weekends only, you waste a lot of time getting equipment into place at the beginning of the weekend and out of it at the end, and have a much shorter time in the middle to do the actual work.

The process could go faster when work is being done in shifts (as it might in the repair from a disaster), but that costs more money.
posted by grouse at 7:58 AM on December 15, 2006

I work for a road maintenance company in the UK (in the head office rather than onsite).

Without knowing exactly what type of multi-year project you're talking about it's difficult to say why it's taking so long. Some projects can go really quickly if we are given a lot of time during the day to work and the job is without complications - conversely we might have to pack up equipment and alter the traffic management twice a day to accomodate the client's traffic obstruction guidelines, and there might be tons of utilities pipes/wires/cables under the road we have to dig around*. In the latter case, we would have a lot less time during the day to work, and digging into roads & pavements would go a lot slower as we would need to be wary of hitting utilities.

Or of course your city might just hire shit contractors who keep making mistakes they have to correct and slack off all the time.

*you have to be really careful around utilities stuff because it's not always documented exactly where everything is. Hit a gas pipe and KABOOM. Hit a power cable and ZAP. Hit a fibreoptic cable and that's a £20,000 repair bill and the council are going to be PISSED that you just cut off their interweb connection.
posted by EndsOfInvention at 8:00 AM on December 15, 2006

I thought this thread was posted yesterday...

Another problem is red tape. If you see construction completely halt on a section of road for a little while, there's a good chance that the government agency in charge of the project and the contractor are fighting out some arcane detail of the contract and specification, and work has halted because during that time there are no progress payments being made to the construction company.
posted by SpecialK at 8:05 AM on December 15, 2006

I thought this thread was posted yesterday...

Yep.

EndsofInvention: One multi-year I totally understand: they are completely re-doing an entire transit mall, including adding a train.

Another, at Naito Parkway (Portland, OR), not so much. I think it may be complicated by utilities, and also by a big sewer project in the area.

I'm not really complaining about these specific projects, but rather am curious about what it takes to build a road--from management to pouring concrete. I'm fascinated by transportation management issues. It's an incredibly complex system, and it kind of amazes me that roads get re-paved at all sometimes.
posted by frykitty at 8:13 AM on December 15, 2006

Somethings you can't rush. If the base has to be compacted and they are doing so by placing an overburden then you just have to wait for the overburden to do it's job.

Supply can sometimes be an issue as well. Here in Calgary we've had overpass projects delayed because the construction boom has concrete plants working at capacity yet still not able to meet demand. Or there might be only a dozen of a particular piece of specialized equipment in the province and theyare already busy on other projects.

Ashphalt ideally should be poured and smoothed when it's hot. Cracks caused when summer poured shrinks in the winter are better than winter poured causing heaves in the summer.

Concrete can't be poured when it's too hot and special (expensive and time consuming) procedures must be used when the temp drops below zero.
posted by Mitheral at 8:31 AM on December 15, 2006

Along the lines of SirStan's link above, consider this one for the Katy Freeway in Houston. The project started in 2003 and is slated to complete in 2009. It is one of the largest highway reconstruction projects in the country.

Several other freeways and interchanges in the area -- US 59, US 290, etc -- are being or have been worked on in the same timeframe, and while not part of the same project, the combined impact on traffic and travel time was and remains amazing.

The comments about having road closures on weekends or at night are particularly apt. Since the highways are major commuter routes, they can't be shut down completely to allow rapid reconstruction, or else the city would virtually shut down as well.
posted by Robert Angelo at 9:09 AM on December 15, 2006

Concrete can't be poured when it's too hot

How hot is too hot? Freeway concrete is poured here in the desert when air temperature exceed 110-115 degrees F.
posted by buggzzee23 at 9:38 AM on December 15, 2006

Two words: job security.

At least that's how things work in southern Florida. Dear God, you're pouring a road, not building the Taj Mahal. There is absolutely no reason it should take that long.
posted by orangemiles at 9:56 AM on December 15, 2006

Often part of the funding for a project comes from the DOT for general interstate upgrades. They get more money for the project in general, but they end up spending a lot of time on things that are not obvious, like wider shoulders, better drainage, improved signage, etc. (Widening shoulders in particular can be a huge project if the bridges/overpasses aren't wide enough.)
posted by smackfu at 10:26 AM on December 15, 2006

Basically, because there's no incentive for it not to. It can go quickly, if there's a real call for it, but that costs extra money. Redoing the S-curve on US-131 through Grand Rapids was a huge pain, but something everyone pretty much agreed had to be done, so they put out extra money for it because 1.) people would go along with it and 2.) keeping it closed longer would be a political failure.

For the most part, though, people accept construction, they complain about it, but jokingly, so it's all about getting as much of it as cheaply as possible, not necessarily about efficiency.
posted by dagnyscott at 10:35 AM on December 15, 2006

Problems we have in Alberta:
1 - an extreme labour shortage
2 - skyrocketing construction costs
3 - a slow provincial government that pays for about 90% of the job (funding which is phased)
4 - not enough companies that can do huge jobs



Concrete can't be poured when it's too hot

How hot is too hot? Freeway concrete is poured here in the desert when air temperature exceed 110-115 degrees F.
posted by buggzzee23 at 9:38 AM P


Concrete can be poured when it's hot. Extreme care must be used to properly cure it, i.e. too much water gets lost to evaporation which messes up the water/cement ratio. They also add stuff to it such as ice and accelerators/decelerators.
posted by Totally Zanzibarin' Ya at 10:52 AM on December 15, 2006

It depends on the mass and the mass:surface area ratio of the pour. A slab is usually fine. However because concrete generates heat while curing large monlithic pours have to watch the internal temperatures doesn't rise to the point that the water starts turning to steam. Things like large cross section columns, abutments, gravity retaining walls (often used around culverts), and bridge decks that aren't precast are all at risk.

Evaporation can also be a problem with high temperatures especially when accompanied by low relative humidity and wind.
posted by Mitheral at 11:42 AM on December 15, 2006

If representative of roadcrews everywhere, this bit of writing by netizen Joel Furr goes a long way toward explaining why it takes so long.
posted by ewagoner at 11:43 AM on December 15, 2006

Evaporation can also be a problem with high temperatures especially when accompanied by low relative humidity and wind. posted by Mitheral

Yep, we have strong winds and low humidity here except in the summer, that's why most pours are done in high heat. Both of my grandfathers worked on the Hoover Dam when it was being built and loved telling us how how miserable that job was. The dam was built by pouring 5 foot deep blocks of concrete that actually had to have cooliing pipes embedded in the pour to absorb the heat of the curing process. Six Companies built a large refrigeration plant to produce chilled water that was then pumped through the embedded pipe. It was the reactive heat rather than the 130 degree ambient heat that caused the problem.
posted by buggzzee23 at 12:15 PM on December 15, 2006