GREENWICH — The construction work that began this fall at the Bruce Museum is only the precursor of a much larger project that is slowly unfolding.

When it is completed over the next several years, museum administrators plan to unveil a world-class facility of art, science and culture in a jewel-box setting overlooking Long Island Sound.

The museum administration worked on the expansion plan for the last eight or nine years before breaking ground this fall. When the project comes to fruition, the Bruce will have a brand new look inside and out, and the museum management is projecting the $45 million expansion will bring in more visitors, showcase stunning new art collections, triple the science-education space and provide new venues for social events.

“It is already a nationally recognized museum,” Bruce Museum Executive Director Peter Sutton said. “And now we’re going to step up our game.”

Supporters of the museum are enthusiastic about the upcoming renovation, which they say will pay dividends for the town of Greenwich and the region. State Rep. Livvy Floren, who has worked with the museum, said the Bruce adds substantially to the fabric of southern Connecticut and boosts the tourism industry.

“The arts — museums, art galleries, historical sites and theaters — are cultural enhancements and economic engines. The expansion of the Bruce Museum, as well as the recent reimagination of the Greenwich Historical Society’s campus, the new Performing Arts Center at Greenwich High School, and the increase in the number of local art galleries, are tangible examples of the vibrancy of our town as a tourist destination, and as a wonderful place to live, work and raise a family,” Floren said in an email.

The centerpiece of the Bruce’s expansion plan is a 40,000-square-foot addition, doubling the current size of the museum.

A consultant, Reed Kroloff, former director at the Cranbrook Academy of Art, a prestigious school of art and design in Michigan, put together a list of 30 architectural firms that had done similar work for consideration, Sutton said. The museum administration eventually settled on a New Orleans firm, Eskew+Dumez+Ripple. Principal architect for the project, Steve Dumez, is a graduate of the Yale School of Architecture.

The proposal from the New Orleans design firm came in with the vision that will connect the building to the landscape, and the heritage of southern New England, Sutton said. “Mostly, we were impressed by their thoughtfulness about what this building should be, and they took into account the history of New England,” he said.

The new addition will be clad in stone, a reference to the stone walls that crisscross the region, as well as the quarries that laid the foundation for a burgeoning Republic, he said. The centerpiece will be an open atrium, filled with white birch trees and other plantings, a “light court.”

“It’s a very nice idea. It will bring light into the middle of the building, and it will bring the external grounds of Bruce Park into the building. It’s connecting the architecture to its surroundings,” said Sutton. “Bring the park into the building, that’s what we try to do again and again.”

The stone cladding will have a glass wall behind it, creating an interesting visual effect. Inside, the feel will be light and airy — and far more spacious and inviting than the current structure.

With the new exhibit space will come renowned works by giants of the modern art world as the Bruce will acquire 16 works by David Hockney. Other gifts include paintings by Pablo Picasso, Lucian Freud, Andrew Wyeth, Edward Hopper and Winslow Homer, all of which will grace the walls of the new addition.

The Bruce has also acquired a substantial collection of early Asian ceramics and Native American art, to complement the expansion. The art collection will be on the top floor of the addition, including permanent galleries. With the new exhibits and facilities, the museum director said visitorship could grow substantially from its annual total of 70,000 to 90,000.

“In the first years, we expect to double our attendance, and expect a 50 percent increase over the long term,” Sutton said.

The museum has always been a center of science education, and that mission will burgeon with the new addition. A new permanent exhibition will be installed, in addition to 3,800 square feet of changing exhibition space, and the facilities for instruction will triple in size. Some 26,000 school kids a year visit the museum for science education.

The current museum has never offered dining facilities to visitors, but that deficiency will be rectified in the new addition. A 60-seat cafe and patio will be built, as well as a venue that can accommodate 500 people for catered events. “This will be a whole new center for entertainment, and an important revenue source for the museum,” Sutton said. A lecture hall with 240 seats can also double as an entertainment space. The mezzanine level of the addition will provide collection storage and an exhibition preparation area, correcting “dismally inadequate” facilities now in use at the museum.

A series of pathways will be added to the grounds, encouraging leisurely strolls and a better showcase for the outdoor sculptures the museum is acquiring.

The layout of the museum will also change, orienting the entrance of the building toward Long Island Sound, not I-95. When visitors arrive, a bank of video monitors will spell out the museums offerings.

Though the new addition will be in the modern style, featuring the latest in digital communications, the institution will preserve the old Victorian mansion where Robert Moffat Bruce, a textile tycoon once lived, as well as the ideals behind the founding of the museum. “Genuine intellectual curiosity” in all forms of human endeavor was part of the museum’s founding credo, its director said, and that mission will continue far into the future.

Bruce deeded the mansion, which was built in 1853, to the town of Greenwich in 1908, stipulating that it be used as “a natural history, historical, and art museum for the use and benefit of the public.”

Workers are currently expanding the parking lot at the museum, a project expected to conclude this month. Renovations on the current facility will take place sometime around the summer of 2019, and the construction of the addition is likely to move forward about a year from now. The project could be completed in 2021, and the director said the multi-phased work was being done in a “deliberate, thoughtful” manner.

When it’s all done, Sutton predicted, “I think it will be a wonderful asset.”