Correction: An earlier version of this article misidentified the person who spoke on behalf of Architectural Resources Cambridge. 

WORCESTER — More than 300 onlookers watched and cheered as a steel beam, covered in student, staff and faculty signatures, was lifted by a crane and carefully placed at the very top of the of UMass Chan Medical School's future education and research building on Monday.

The nine-story, nearly $350 million structure is slated to open in 2024, and will house 77 rare-disease researchers who specialize in gene therapy, molecular medicine and neuroscience.

"We recognize that there are many rare diseases — 7,000 actually — and that by putting scientists together to work on the science and clinical needs of patients of those diseases, we hope that we can actually change the course of history of disease," UMass Chan Medical School Chancellor Michael F. Collins said. "That's our construct for the new building."

Collins said he was excited by the turnout for the ceremony, which included members of the newest class of medical students, Iron Workers Local 7, and Shawmut Design and Construction workers wearing yellow vests. 

The placement of the 350,000-square-foot building — sandwiched right in the middle of the medical school, UMass Medical Center and Albert Sherman Center — was strategic, Collins said. 

The ongoing theory, Collins said, is that if "great scientists" are put into a "great building," then "sparks will fly."

Collins was joined by Les Hiscoe, chief executive officer at Shawmut Design and Construction; Barbara Kroncke, executive director at the University of Massachusetts Building Authority; and Bryan Thorp, associate principal at Architectural Resources Cambridge. 

After finishing their speeches, workers secured the beam to the crane. The beam had an American flag on one side, and a tree on the other. 

"The tree represents our expression of good luck and goodwill to the future inhabitants of this building, and a tribute to the hard work of those who have built it," Hiscoe said.

With the final of 5,873 steel beams placed today, the steel skeleton frame of the building is now complete.

Workers will move onto the next phase of construction, which includes the installation of the roof and exterior "curtain wall" made up of a system of glass and steel panels, a release from the university said. 

The plan, the release said, is for the the building is "weather-tight" by winter, which would allow interior work to begin. 

"We're fortunate to have a Board of Trustees and a president of the university that understand the importance of this," Collins said. "Right in the middle of COVID they made a commitment to it is really pretty special. Very exciting."