Thirty-eight cement trucks will rumble out of Halawa before midnight tonight and head to Makiki to begin unloading 6,000 tons of concrete in an unusual operation that will disrupt traffic around Kalakaua Avenue and Young Street through Saturday morning and possibly into the afternoon.

When the work is done, 300 truckloads will have pumped 2,900 to 3,000 cubic yards of concrete into a massive, steel-bar-reinforced hole to form the foundation for the 24-story Holomua condominium.

That’s enough concrete to cover a football field in concrete 16 inches deep.

And as in football, the game-planning, patterns and timing have to be precise.

"These things are highly coordinated," said Jack Almanza, general manager for concrete and sales for Hawaiian Cement, which is providing the trucks, drivers and concrete. "There’ll be a whole line of headlights (staging at Hawaiian Cement) and then — boom — everyone takes off because you want a steady flow of concrete."

Each of the 38 drivers has just 90 minutes after leaving the concrete plant to reach the job site and unload before the concrete begins to harden, said Peter Savio, who is developing the 176-unit condo.

"It will take a while before we figure out the rhythm because it will be like a conveyor belt of trucks rotating in and out," Savio said. "This is going to block traffic, but we want to be good neighbors."

Savio and his construction team had considered the more common method of driving piles to anchor Holomua’s foundation — a noisy process that would have lasted weeks, bothered neighbors and likely caused cracks in nearby buildings, Savio said.

Instead, Savio said, they chose the less typical method of pouring a giant "mat pad" of concrete into a rebar-filled pit that ranges from 3 to 7 feet deep.

"The ground is solid, and a mat pad is a lot less hassle that won’t cause stress on the other properties," Savio said. "Even if it’s a little more expensive to do a slab, it’s cheaper in terms of the inconveniences and cracks and repairs to other buildings. You cause cracks, you’re responsible."

The first trucks to arrive at the Holomua construction site at 1315 Kalakaua Ave. will begin unloading just after midnight, and Savio hopes the last truck will pour the final load by 10 or 11 a.m. Saturday.

But unforeseen delays caused by traffic, or malfunctions to any of the five pump trucks offloading the concrete along Kalakaua Avenue or Young Street, could delay completion until 3 p.m., he said.

Each truck will carry 10 cubic yards of concrete from Hawaiian Cement’s Halawa plant. By comparison, it takes three truckloads to form the foundation for a typical suburban house, Almanza said.

Savio needs 300 truckloads of concrete. So Hawaiian Cement will need to have each of its 38 drivers drive eight round trips between Halawa and Makiki, Almanza said. (There are about 80 concrete trucks on Oahu among the island’s three concrete companies, Almanza said.)

Once the drivers pull up to the pump trucks at the job site, they’re expected to take no more than five minutes to offload.

"It’ll be a high-speed delivery so we can avoid traffic so we can get this done," Almanza said. "There are a lot of benefits to night: It’s cooler and there’s much less traffic. Hopefully it’ll be a clear run to the project."

While many of Waikiki’s major hotels and some recent high-rises were built on mat foundations, Almanza said Savio’s plan is still unusual on Oahu.

"There are many, many mat pours in Honolulu," Almanza said, "but we haven’t had one this big in a while."

The project also means that every one of Hawaiian Cement’s 38 drivers will be earning extra pay for working 10 hours — and possibly longer — beginning in the middle of the night.

"Everyone’s happy to be working," Almanza said.