When Tim Hester began his career as a young lawyer at Covington & Burling in 1983, the one spot in the office he was sure to bump into his fellow associates was the firm’s law library, an expansive collection of legal encyclopedias and texts that took up an entire floor of Covington’s previous office on Pennsylvania Avenue.

“When I started here, there were no computers in lawyers’ offices,” said Hester, who is now the chairman of the 850-attorney law firm. “The central hub was the library, that’s where you’d see people all day.”

Over time, as technology evolved, the library — like that at most corporate law firms — shrank dramatically. The library at Covington’s new headquarters at CityCenter, which the firm moved into this week, is about a third the size of the library at the previous location. That left the question of how to design a new type of communal space that made sense in the modern era.

“When you lose that [library], you scratch your head about how to create those gathering spots and make it feel alive,” Hester said.

So Hester worked with John Waters, the law firm’s executive director, and a team of architects led by Debra Lehman Smith of LSM to design an office that includes 72 communal areas, including 36 conference rooms and additional informal spaces such as eating areas and lounges. It also had an updated, streamlined look: The wooden floors, oriental rugs and most of the antique furniture have been replaced by white stone floors, full-length glass windows and abundant natural light.

The new space is 420,000 square feet, about 7 percent smaller than Covington’s previous headquarters. Offices for partners are almost 40 percent smaller, shrinking from 300 to 190 square feet. The firm is saving about $50 million over the course of the lease, which is for 20 years with an option to extend for an additional 20 years.

Covington is not the only major law firm in Washington to relocate recently. At least half a dozen major firms have done so, or have announced such plans, since 2011. And most are downsizing in real estate, the second-largest expense for law firms after personnel.

But the move for Covington, one of Washington’s oldest and most well-known homegrown law firms, to CityCenter — a mix of retail, residential and office space that is said to redefine downtown D.C. — is perhaps the most telling sign of how law firms’ push to become more modern and efficient is affecting commercial real estate in Washington.

Since the recession, more than 20 law firms in the District have shed space, and the size and frequency of those contractions have increased since 2012, according to a March research report by Savills Studley, a commercial real estate services firm.

Between 2005 and 2007, large law firms leasing at least 50,000 square feet expanded a combined 1 million square feet in downtown Washington. But between 2010 and 2013, large law firms contracted a collective 270,000 square feet. The report defines downtown as the three submarkets where most law firms are located — West End, Central Business District and East End.

The shrinking law firm footprint is leaving a major gap in the local real estate market, because the firms account for 24.6 percent of office space in downtown Washington — by far the largest private industry, rivaled only by the federal government, which occupies 20 percent of office space downtown, according to the report. So far, other private businesses have yet to take the law firms’ place.