The city might eventually have to build additional steel-and-concrete columns to help support several elevated rail stations in West Oahu, according to the rail project’s top executive, if the cracking in existing columns there is deemed bad enough.

Building such added columns, known as “hammerhead piers,” could take awhile, Honolulu Authority for Rapid Transportation Executive Director Lori Kahikina told Honolulu City Council members on Tuesday.

Still, the agency is prepared to take the necessary steps to ensure the elevated structure there is safe, she added.

Kahikina told the City Council’s Transportation, Sustainability and Health Committee that she “hopes it’s the last” problem to impact construction along the western half of the rail line, which is almost completed.

“It might not be,” she added.

The future rail stations at University of Hawaii West Oahu, Ho’opili, Waipahu, West Loch and Pearl Ridge are affected by the potentially significant problem, Kahikina told committee members.

HART and its contractors still haven’t determined who’s at fault for the growing cracks. The contractors for that work were Kiewit Infrastructure West and HNTB.

The structural engineering firm Consor first discovered earlier this summer during inspections for the Department of Transportation Services that the pier cracks were growing, according to Kahikina. The firm recommended that no one stay on the affected station platforms until further analysis could be done to ensure they were safe, she added.

Kahikina told the committee that it remains safe to run the system’s driverless trains along the guideway because they run down the center of the elevated guideway and there’s no cracking directly underneath there. The cracking that has officials concerned, meanwhile, is forming under the platforms that jut out on either side of that guideway.

Consor and a separate engineering consultant for HART, Wiss Janney Elstner Associates, should deliver their findings on the cracking in six to eight weeks, Kahikina said Tuesday.