Today the Washington State Department of Transportation provided a wrap-up on the replacement of concrete panels on northbound I-5 through Everett, Washington. WSDOT says they are done addresses a few issues that happened along the way. Here’s their story written by Kurt Batdorf at WSDOT.
There’s never a good time to close lanes to do road work.
Any day, and any time of any day, we pick to close lanes will inconvenience and annoy a lot of people because there’s just a lot of traffic these days. Weekends tend to be less busy than weekdays and people are typically more able to adjust their plans on weekends than during the work week.
This is why so much of our major work, like this past weekend when we reduced Interstate 5 through Everett to one lane around the clock to replace concrete pavement panels, happens on weekends. We need several days in a row to do the work and allow the concrete to harden, and that is better accomplished on weekends than weekdays when most people need to get to work at specific times.
But isn’t January too cold, too wet, too unpredictable for construction?
Almost always, yes. In this case, we got lucky with contractor availability and weather.
We covered why this work needed to happen in a previous blog but in short, we needed the contractor to replace the panels sooner than this spring – which was the original plan – to avoid another emergency closure like we recently had.
Our engineers and contractor Acme’s project manager mulled options. The weather forecast for Jan. 21 and 22 looked like it’d be just warm enough and not too wet. Acme could work that weekend, but they’d need to work around the clock, night and day, to pour concrete that spread across all lanes of the freeway. That meant we could only keep a single lane open to create space for a safe work zone. The plan firmed up on Tuesday, Jan 17.
The weather forecast was a big motivator and a bigger variable. The type of cement we specified for this project can be poured when it’s raining, which is good, because it rained on Saturday while the work was happening. The challenge is it won’t cure properly if it’s near freezing, and we were awfully close to those temperatures Friday and Saturday nights, but luckily, it stayed warm enough.
Fortunately, Acme anticipated the weather. Crews used heated water in the quick-set concrete mix to speed up the cure time. They then covered each new slab with plastic and fabric to protect the concrete as it hardened, eventually getting strong enough to support full vehicle weight. Under ideal circumstances this takes two to three hours, but Acme wasn’t working under ideal circumstances. While it stayed warm enough to get this done, it was cold enough that it took the concrete longer to set than it would on a warm summer day. This is why it may look like no work is happening when you drive by construction sites: There just isn’t much to see when concrete sets.
The good news is Acme finished the work and had all lanes reopened by 7:15 pm Sunday, almost 10 hours ahead of schedule. Acme also refreshed the temporary lane striping to make it more visible for drivers. They’ll install permanent striping after they replace bridge expansion joints in the spring, which will require more lane shifting.
So why not do this on other projects?
So, if we were able to pour concrete and get this done in January, why not do it for other projects rather than waiting until summer?
It’s a fair question.
Construction lead Cody Filey said it’s unusual for us to have temperatures favorable enough over several days this time of year to be able to do a project like this. And while we can do things like using burlap covers, plastic sheets and water heaters to battle the elements, we can only do that to a certain point, and it makes the project more expensive because of the extra materials, time and labor. When it gets too cold, concrete just doesn’t cure fast enough or properly enough to be able to reliably reopen lanes to traffic.
It also helps that, while the scope of this project was big, it wasn’t nearly as large as the work we do in the summer. The largest hole Acme filled was 12 by 47 feet, but most were only 12 by 16 feet. The quick-set concrete can be poured in the rain even when it’s close to freezing. That’s not the case for the polyester-reinforced concrete we use on Revive I-5 bridge decks in Seattle and expansion joint projects, which while a stronger, better option for those bridge decks, we can pour only when the surface is bone dry, it’s well above freezing and there’s no chance of rain.
Could we repeat this on a larger scale, say, over several hundred or several thousand continuous feet of new concrete and work through the winter? It sounds appealing, sure, and we would love to. We just can’t count on the weather to be as cooperative as it was this past weekend.
That said, we know it was challenging for many of you. While we did a full-court press in terms of getting the word out through our various communications channels, it’s impossible to reach everyone and we know some of you were surprised. We appreciate your patience while we got this work done and we’re happy there is fresh new concrete and lane striping for drivers through this busy section of Everett.