There are at least two visible ways to gauge the vitality of a college campus: The bustle of students flowing through it over the years, and the hectic action of hard-hat crews building and upgrading the place.

Trinity Washington University, a Roman Catholic women’s school, has recruited a steady stream of young women from low-income neighborhoods in and around the nation’s capital during the past two decades. That pipeline, plus the growth of co-ed graduate programs, enabled Trinity to weather market pressures that forced other women’s colleges to close or start recruiting undergraduate men.

But the 119-year-old school, on a placid campus in Northeast Washington, D.C. dotted with magnolias and statues of saints, has not opened a new academic building in more than a half century. On Saturday, that will change as Trinity dedicates a $38 million classroom and laboratory center for subjects from clinical nursing to microbiology.

“This solves our major academic challenge for a good long time,” said Trinity President Patricia McGuire, who has led the 2,300-student university since 1989.

Before commencement on May 21, the university gave students a sneak peek of what will be called the Payden Academic Center, an edifice of four stories and 80,000 square feet under a red tile roof. They were stunned at the modern, climate-controlled classrooms and labs, McGuire said. Some cried tears of joy. Some said they wanted to change their majors because they loved the look and feel of the labs. “That’s really cool,” McGuire said.

Founded by the Sisters of Notre Dame de Namur in 1897, Trinity holds a distinct niche in the Washington region’s higher education network. Located on Michigan Avenue NE, next to Catholic University, Trinity was long viewed as a destination school for middle-class women who wanted a Catholic liberal arts education. House Democratic leader Nancy Pelosi (D-Calif.) and former health and human services secretary Kathleen Sebelius are among its alumnae. But its enrollment plummeted after colleges across the country went co-ed in the 1960s and 1970s.

Under McGuire, Trinity has repositioned itself to serve disadvantaged students graduating from D.C. public schools and elsewhere. Its tuition and fees are about $23,000 a year, much less than many private schools charge. Even so, nearly all undergraduates receive financial aid. About 80 percent of first-year students have enough financial need to qualify for federal Pell grants. More than 80 percent of undergrads are black or Hispanic.

To survive as a low-tuition women’s college requires tight control over spending. Nothing gets built at Trinity without years of planning.

“We only do one building per generation,” McGuire joked. “I’ve been here long enough to do two.”

McGuire’s first big project was an athletic center with a gymnasium and indoor pool, which opened in 2002. That complex helped rejuvenate the campus and boost recruiting. Then McGuire set her sights on a new academic center to replace an aging science building and augment the classroom space in the university’s 225,000-square-foot Main Hall. The last academic building to open on campus was a library in 1963.

McGuire landed the university’s largest donation ever in 2013, a $10 million gift from Joan Payden, an alumna from the class of 1953. That jump-started funding for the center, which will be named for the Payden family. Ground broke in May 2014. The project was such a big deal that the university set up a time-lapse camera to show it taking shape:

Trinity Washington University, a Catholic women’s school in Northeast Washington, is building a $40 million academic center that is expected to open in August 2016. (Trinity Washington University/Phil Reese)

University officials showed off the center this week ahead of the dedication. Inside the main entrance is a rotunda with columns, to hold receptions and other events. There are 23 classrooms, including two tiered rooms that can serve about 70 students each — larger than anything previously available on campus. There are eight science labs for subjects from anatomy to chemistry. There are two nursing labs, including one outfitted with robotic mannequins — representing a mother and two infants — that can demonstrate a simulated birth.

“It’s a new era, a new opportunity, a new beginning,” Mary Romanello, dean of nursing and health professions, said of the Payden Center. Romanello, who was checking out the new “sim-mom” Thursday in the birthing lab, said students are excited for the coming school year.

“It not only changes their mindset,” she said. “It also changes the things we can do.”