After their initial review of the cracks forming on rail’s hammerhead piers, city-hired consultants and the engineers who designed those large station supports did not hold the same view on just how bad the problem was, according to newly released documents.

Wiss Janney Elstner Associates, which was hired by the Honolulu Authority for Rapid Transportation, initially determined that the shear cracks “did not pose an imminent concern,” according to the latest federal oversight report on rail that’s been made publicly available.

Patching and sealing would sufficiently address the cracks, that engineering firm concluded.

At the same time, however, HNTB – the engineer of record that designed those station piers – still had concerns about the cracks, according to the report from the rail’s project oversight contractor, Hill International. The company opted to “do more analysis of the load-bearing capacity of the piers.”

Rail hammerhead pier Waipahu
Hammerhead piers, pictured in the foreground, support rail’s future Pouhala station in Waipahu. Rail officials have said cracks forming in such station-supporting piers on the westside could be the project’s next big problem. Cory Lum/Civil Beat/2022

“HNTB believes that it should have included more rebar (reinforcing bars) in the piers in the areas that the cracks occurred,” the Hill report says. HNTB planned to keep evaluating “the appropriate remedy” and then deliver its final report to HART by the end of September.

That final report still hadn’t arrived as of Oct. 22, however, and the status of HNTB’s evaluation into the appropriate remedy is unclear.

HART has received “preliminary information” on the hammerhead cracking from its consultants, but the parties haven’t yet finished their analyses and the rail agency doesn’t want to rush their work, according to Executive Director Lori Kahikina.

The latest Hill report, which provides a third-party update on the Honolulu rail project through August, offers a glimpse into that preliminary information on the hammerhead piers. HART released the Hill report ahead of the agency’s Friday board meeting.

When asked about the content of the Hill report, HART spokesman Joey Manahan stressed in an email Thursday that HNTB has finalized neither its analysis of the situation nor its recommendations on what to do about it.

Nonetheless, “to the best of HART’s knowledge, HNTB’s initial beliefs have not changed,” Manahan added.

Two Possible Pathways

The structural engineering firm Consor first discovered that the pier cracks were growing during inspections this past summer for the Department of Transportation Services, according to Kahikina.

HART officials have said the problem affects five future stations, at University of Hawaii West Oahu, Hoopili, Waipahu, West Loch and Pearl Ridge.

Consor is also doing its own analysis of the issue. When it initially flagged the growing cracking, Consor recommended that no one stand on the affected station platforms until further analysis could be done to ensure they were safe.

Lori Kahikina: “If the hammerheads are not addressed we are not handing this over to DTS.” David Croxford/Civil Beat/2022

The problem appears limited to piers that aren’t reinforced with what’s called post-tensioning, a construction technique in which tightened cables help to support those concrete structures’ piers, according to HART Project Director Nathaniel Meddings.

In an interview with Hawaii News Now last week, Kahikina said that all of the discovered hammerhead cracks would have to be epoxy coated. Several of those cracks would also need more extensive repair work, and structural engineers are considering two different methodologies for the additional work, she added.

No details on those methodologies has been made available, although Kahikina said that structural engineers were expected to decide this week which one they should use.

The city now aims to open rail’s first 10 miles to Aloha Stadium early next year for passenger service. Officials have said trial runs on the west side remain safe because the driverless trains move down the center of the elevated guideway, where there’s no cracking.

The issue could further delay that partial opening, depending on how extensive the repairs need to be.

“If the hammerheads are not addressed we are not handing this over to DTS,” Kahikina said at a recent press briefing. The city’s Department of Transportation Services will oversee operations and maintenance of rail.

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