LATHROP (CBS13) – In order to repair Highway 99 in just 99 hours, Caltrans is using a technique that’s never been done on this scale in the Sacramento area. They’re literally putting the pieces in place.

Men in hard hats were hard at work at a Lathrop construction facility, all for the big 99 hours of construction ahead and plenty of other projects.

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Caltrans began its major multi-million-dollar project on Highway 99 on Friday night.

“This is probably one of the biggest closures we’ve had in the Sacramento region,” Angela DaPrato with Caltrans said. “This is impacting a lot of people in Midtown, Downtown and all different commuters coming in from different directions.”

The Fix Sac 99 project will stretch from the U.S. 50 connecter to 47th Avenue to repair the bridge deck, all within four days’ time. It’s able to do that using pre-cast and pre-stressed concrete pieces to efficiently plan and do the construction.

“It’s better pre-fabricate and pre-make everything and have it all ready to go so that when they demolish the old bridge and bring in this new one, it’s going to go seamlessly,” Michael Hein, president of Con-Fab California, said. “And, so that the shutdown is not going to be hindered.”

The plan was to know how the pieces would fit even before construction starts.

“We’re actually doing a lot of pre-work ahead of time. So it’s almost like a rehearsal for the big game,” DaPrato said.

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Caltrans told CBS13 it’s deciding to go this innovative route for building Highway 99 based on the success of using this method in other parts of the state.

“This accelerated bridge construction method was very successful in the Echo Summit. This is the first time we’ve really used this magnitude of the accelerated bridge construction method in (the) Sacramento region,” DaPrato said.

With the bridge deck construction, the girders will be placed tightly together, then an ultra-strong concrete will be laid in between – fusing them together. Then another layer of concrete is put on top to finish the job.

Fast and easy without losing efficiency and quality.

But, if you’re thinking about hitting the road in the next four days, avoid 99 while they’re building 99.

“Please be patient. Caltrans is doing this within four days. We’re trying to get the work done as soon as possible,” DaPrato said. “It’s necessary work but it’s also proactive work, so it doesn’t cause a bigger closure down the road.”

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Caltrans is recommending people take Interstate 5 during the closure to avoid any traffic.