Six aging structures along the historic Hana Highway on Maui are chosen for major improvements

The winding drive to Hana is as much about the journey as the destination. The section of Hana Highway from Huelo to the quiet East Maui town features roadside waterfalls, tropical greenery, fruit stands and sheer coastal vistas for the 1,500 vehicles on average that travel daily on the two-lane highway, mostly tourists and residents for whom it is the primary link to the rest of the island.

The state Department of Transportation maintains approximately 29 miles of the highway, also known as Route 360, in the Hana Belt Road Historic District, which includes 43 bridges and 12 large culverts. Many of the one-lane bridges were built more than a century ago and are obsolete by modern traffic safety and load standards. DOT says necessary repairs and improvements far exceed routine maintenance.

With so many structures needing serious fixes and limited funding available, the agency has identified six bridges that require more immediate attention. The chosen bridges — Kailua, Maka­nali, Puohokamoa, Kopiliula, Ulaino and Mokulehua — were built between 1908 and 1929 and are among those with the lowest load ratings and greatest maintenance needs, according to DOT.

The $37.3 million bridge rehabilitation project aims to “improve six bridges in a context- sensitive manner so they are safe and functional for highway users,” the agency said. It is historic in its own right as the first major bridge rehabilitation project on Hana Highway and the first in the state to replace bridge decks using a lateral slide-in method that will minimize costs and traffic impacts, according to DOT Maui District Engineer Robin Shishido.

The project is in the environmental review and design process. DOT hopes to finalize designs by late 2022, with construction projected to start in spring 2023, one bridge at a time. It would take roughly a year to complete work on each bridge project, although Shishido said it’s possible some of the work could be done concurrently, depending on available funding.

For many East Maui residents, improvements to the deteriorating structures couldn’t come soon enough.

“We need it now,” said Claire Kamalu Carroll, 52, a Hana Community Association board member. She explained the highway is a lifeline for the small, remote communities along East Maui, and there are worries that worsening conditions and outdated 10-ton weight limits could disrupt deliveries of gasoline and other essentials.

A secondary route south of Hana along the “back side” of Haleakala has its own challenges, according to Carroll, who travels to Central Maui for weekly overnight shopping trips for herself and Hana kupuna who can’t make the arduous drive themselves.

She said she is grateful the project has been funded, but is “bummed” that construction won’t start until 2023.

“It’s very necessary. The bridges were designed to last 75 years, but now it’s over 100 years,” Carroll said. “I’ve seen it firsthand, and it’s just a matter of time. We’re just crossing our fingers that these bridges hold.”

Problems cited in DOT studies include bridges lacking the minimum 16-foot width for one-lane traffic, railings that don’t meet crash standards, unreinforced structural elements such as abutments and wing walls, and difficult-to- maneuver approaches.

Some of those same problems are considered “character-defining features,” the reports say, creating a challenge for engineers and contractors to maintain the historic nature of the bridges while ensuring upgrades satisfy current safety codes and can handle an increase in load-carrying capacity to 40 tons.

Only one bridge‚ Kopiliula, built in 1926 or possibly 1914, is recommended for total replacement due to structural conditions. DOT plans call for the existing structure, which is 14 feet wide and 77 feet long, to remain in place but be permanently closed to traffic and a new two-span concrete bridge erected alongside it.

The bridge is one of five historic Hana bridges adjacent to the man-made East Maui Irrigation system, a historic feature on its own, and the only one with a dam and sluice gate equipment incorporated into its support system.

Plans for the other five bridges add new substructure components to bolster the existing supports and install new decks and railings using a lateral slide-in method — the first time it’s been employed in Hawaii, according to Shishido.

The technique involves building temporary supports on one side of the existing bridge for construction of a new bridge deck. While the existing bridge remains open to traffic, the new deck is built on the temporary supports, and new bridge supports are built behind the existing ones.

When ready for installation, the existing deck is removed and the new deck slid into place by a hydraulic system.

“Definitely, the constructability is a big challenge,” Shishido said. “Hana Highway is a narrow, winding road, and it’s the primary route in and out of the Keanae and Hana areas and it’s also a high tourist attraction area. So when the consultant looked at the option to replace these bridges, the slide-in option was the best alternative for construction.”

Although traffic will remain open during most of the construction, Shishido said the highway will have to be closed anywhere from three to four days when it’s time to remove the existing deck and slide in the new one.

For all six bridge projects, any new construction will be designed in the same style as the original, he added.

Another major challenge is minimizing construction impacts on a vulnerable highway already under pressure from over-tourism that has generated hostility in many East Maui residents.

Shishido said most of the bridge work will take place at night whenever possible. Construction activities at the bridge locations also might require temporary construction easements from adjacent landowners.

The DOT said public comments about the project so far have centered on shortening the construction schedule and minimizing traffic impacts, retaining the bridges’ historic character, keeping them as single lanes and providing long-lasting solutions.

“One of the concerns the community has had is that now that you upgrade these bridges, the heavy loads and big tour buses can come in,” Shishido said. “But keep in mind we’re only replacing six out of the 50-plus bridges (along the entire highway), so we still have the limitation of size and weight limits.”

The DOT, in partnership with the Federal Highway Administration’s Central Federal Lands Highway Division, held its latest public meetings on the project in September and plans for more in 2022.

Due to COVID-19 concerns, the last meetings were conducted virtually. Ipo Mailou, 44, president of the Hana Community Association, said many kupuna and others in the community are not tech-savvy enough to have tuned in, and she urged more in-person information sharing.

The Hana native said she’s not “grumbling” about the needed upgrades, but has many questions and concerns. These include the construction impacts on local traffic and residents like herself who live next to the historic bridges and those who farm or operate fruit stands and other businesses near the structures.

Mailou said she also wants to make sure the bridge makeovers fit in with the area’s rural character and don’t resemble something that would be built on Oahu.

“The bridges are our kupuna; they hold history, they lead you to someone’s home, they lead you to water, they lead you to Hana, the heart of Maui and Hawaii,” Mailou said.

“I just hope everybody who is planning, and the repair guys and the construction guys, always keeps in mind that once you do something, do it right and make sure it’s something that when you leave the job that you did your best and the community is happy with it, they’re happy with it, and that we’re not doing it for tourism only. We’re doing it because we need it for us.”

Shishido said that eventually, the other three dozen or so historic bridges of Hana Highway under state jurisdiction will be improved and that work on the first six “will set the precedent for how the other bridges get done.”

TO LEARN MORE AND COMMENT

>> For more information and to provide comments on the Hana Highway Bridge Improvements Project, visit the project website at hanabridgeimprovements.com.

>> Comments also can be sent to project manager Tom Kubicz via email to tomasz.kubicz@dot.gov or by calling 720-963-3498 or 202-981-4183.