After the Navy completed a multi-million dollar renovation on the space, Navy Yard workers returned to building 197, where contractor Aaron Alexis went on a shooting rampage on Sept. 16, 2013. (AP)

They begin returning Monday to the place where they hid beneath desks, barricaded themselves behind office doors and fled down corridors as 12 colleagues were shot to death at the Wash­ington Navy Yard.

Some Navy Yard workers are looking forward to going back to Building 197 and regaining a sense of normalcy 17 months after the shooting rampage. Others are so traumatized that they can’t bring themselves to reenter their old workplace, where contractor Aaron Alexis stalked cubicles, hallways and stairwells with a ­sawed-off Remington shotgun on Sept. 16, 2013.

Beth Ann Cordova lost two co-workers that day: Michael Arnold and Richard “Mike” Ridgell. A third person she is close to, Jennifer Bennett, was badly wounded.

Cordova, a 55-year-old executive assistant and data manager, said she will steel herself to head to her new desk inside the renovated building. But there are certain parts of Building 197 that she would rather avoid, even after a tour several weeks ago designed to ease her fears.

“I did not wish to go anywhere near where Jennifer had been shot, and I still don’t,” Cordova said. “He hurt my friend. I could have lost her.”

Vice Admiral William Hilarides discusses Building 197 at the Navy Yard, the site of a mass shooting 17 months ago. (Bill O'Leary/The Washington Post)

Cordova knows a group of people who refuse to go back to Building 197, the headquarters of the Naval Sea Systems Command. The Navy has accommodated their wishes by transferring them to other jobs in other buildings, said Vice Adm. William Hilarides, who leads NAVSEA.

Dozens of other workers have retired rather than return, even as the Navy has completed a $6.4 million renovation of the building to erase the worst memories of the mentally ill Alexis, 34, who was killed that day by police.

The overhaul of the building includes new offices, doors, windows, carpet and paint. Even the entrance, where Ridgell, a 52-year-old security guard, was killed, has been moved. Outside, there are concrete steps, benches and windows where the entrance used to be.

“In fact, you can’t find vestiges of it,” Hilarides said. “Several of our folks dragged Mike out after he had been shot and tried to save him in the parking garage. So there is a lot of emotion about that.”

About 2,800 workers are expected to return to the sprawling building Monday. Inside the entry area, there is a space dedicated to the 12 people who died in the shooting: Ridgell, Arnold, Martin Bodrog, Arthur Daniels Sr., Sylvia Frasier, Kathleen Nark Gaarde, John Roger Johnson, Mary Frances DeLorenzo Knight, Frank Kohler, Vishnu Pandit, Kenneth Bernard Proctor Sr. and Gerald Read. The memorial was unveiled Sunday to the victims’ families.

The building’s redesign includes soothing new paint colors — daffodil yellow, freshwater blue, parakeet apple green. There is a new cafeteria and visitors’ center near a Starbucks kiosk. Soundproof glass walls enclose a former atrium to help reduce noise.

The building has been renamed in honor of Joshua Humphreys, who designed the first Navy frigates. Hilarides said a new name was an important reminder of NAVSEA’s resilience.

Flowers rest on an anchor outside a gate at the Navy Yard, the site of a mass shooting 17 months ago. It’s scheduled to reopen on Monday. (Bill O'Leary/The Washington Post)

A task force of NAVSEA employees oversaw the renovation of the historic brick building, which had been used during World War II to assemble guns for battleships.

During the renovation, Building 197’s workers were relocated to a former Coast Guard facility at Buzzard Point in Southwest Washington.

On Saturday, movers began carrying in files and installing computers for the first wave of returning workers, said Rory O’Connor, a NAVSEA spokesman. Other workers will return on a staggered weekly move-in schedule over the next nine weeks.

Hilarides acknowledged that some workers are struggling with the return. To help, NAVSEA organized groups of workers to tour the building in small groups in recent weeks.

“We didn’t want anyone to say, ‘The first day I go back in the building is the first day I go back to work,’ ” he said.

Cordova said her tour was extremely helpful. “I was on the ‘Who’s going to have a problem?’ tour, ” said Cordova, who was reassured by all the changes she found. “It looked different, and I thought, ‘I can deal with this.’ ”

But not everyone came to that conclusion. One woman on a different tour started having an anxiety attack a quarter of the way through the first floor and had to leave, according to someone who was with her. She isn’t scheduled to move into the building until March and will try to visit again.

Accommodations are being made for those too traumatized to return, Hilarides said.

“The people who knew themselves well enough and said, ‘I could never go back’ have found a new path,” Hilarides said. “Many have retired.”

O’Connor said that 132 employees retired between Sept. 15, 2013, and Dec. 31, 2014 — but officials could not break out how many were prompted by the shooting. Some had been offered early retirements to help with budget cuts.

Some workers said they were eager for the return, which would provide them with a sense of closure.

“I’m fine with returning to the building,” said Marine Col. Dave Thompson. “I’m looking forward to being back in a more stable and permanent setting.”

Nidak Sumrean, director of cost engineering and industrial analysis for NAVSEA, said he, too, would welcome a new normal. “For me,” Sumrean said, “getting people back into the building will allow us to finally come to closure after this bad situation.”

Paul Anderson, a Navy commander and chaplain, said support teams, including chaplains and employee assistance personnel, will help people “reinhabit” the building.

“The Navy has done a wonderful job of re-creating that space so that it won’t be haunted by memories and by the unresolved emotions of people who were there that day,” Anderson said. “They have done a herculean effort at reclaiming and rededicating that space. There may be people so traumatized they don’t feel comfortable about being back in there. Some will have to figure out ways to expunge their fear. But the institution has done as much as they can to make the building a safe place.”

Many NAVSEA employees have healed by sharing stories from the day of the shooting, said Hilarides, who was locked down in his office with 12 people for more than two tense hours.

“There was a feeling of powerlessness,” he recalled. “I’m in command of 60,000 people, and I can do nothing. I’m locked down with my phone.”

Ultimately, Hilarides said, the shooting has made NAVSEA a more resilient organization. “To make very, very strong steel, you put it in the fire. You bang it with a hammer,” he said. “I see this event as tragic. It has forged us into a family.”