Art comes first in a worthy expansion.

When the Los Angeles County Museum of Art announced last year that it would tear down most of its Wilshire Boulevard complex to erect a powerful new edifice by architect Rem Koolhaas -- at a cost upward of $400 million -- it did not go unnoticed that LACMA was unlikely ever to consider raising that kind of money to buy art. The San Francisco Museum of Modern Art, the Guggenheim Bilbao, London’s Tate Modern, the Milwaukee Art Museum -- it’s customary these days for expensive new art museum buildings to be constructed with great fanfare, while the bothersome question of what might be shown inside is left for later.

Now, the Modern Art Museum of Fort Worth has revived a different model -- and a very welcome revival it is. Art is in the driver’s seat of its terrific expansion project, which opens to the public Saturday, while museum architecture has been recognized as a critically important art with specific social functions. The elegant new building, designed by Japanese master Tadao Ando, has been carefully devised for one paramount purpose: creating opportunities for intimate encounters with individual works of art.

In the nearly seven years that the Fort Worth expansion has been underway, with director Marla Price at the helm, the museum’s collection of painting, sculpture and other postwar art has also been transformed. It has gone from trifling to impressive. Sources report that between $40 million and $60 million was spent on additions to the collection -- a figure that approaches the $65 million cost of the new building. Art worth intimately encountering is now everywhere to be seen.

One-third of the 153,000-square-foot building is devoted to gallery space, mostly in a sequence of three two-story pavilions. A shallow reflecting pool extends from one side of the ground floor, while a grassy sculpture garden extends from the second floor on the other side. As you move through the spaces, encounters with art alternate with tranquil views through enormous windows.

Although the architectural style is different, the scheme recalls the J. Paul Getty Museum in Los Angeles, with its two-story pavilions, intimate rooms and restful outdoor breathing spaces between them. Forget fatigue. Despite the Fort Worth building’s size, refreshment mark this museum experience.

Larger galleries are found in the building’s center, but no single gallery is huge. Some even consist of bays that hold a single work of art -- a magnificent recent painting by Susan Rothenberg, for example, all rustling brushwork and nervous energy, or an exquisite photographic diptych of the tangled, asymmetrical rhythms of a Chinese forest by Thomas Struth. On the floor in one glass-enclosed space surrounded by water, Carl Andre’s elemental path of steel plates split by a narrow line of copper snaps your body to attention, much the way magnetic north grabs a compass needle.

Given such intensely focused encounters, weak work fairly withers. In the same kind of space that Andre electrifies, a slight bronze sculpture by Cy Twombly just wilts.

The museum now has five times the exhibition space it had in its former home around the corner -- a pleasant Bauhaus-style building by German expatriate Herbert Bayer. This being Texas, museum spokesmen like to brag that the new museum is second only to New York’s Museum of Modern Art in gallery space for postwar art. The comparative list of other museums’ gallery space that they’ve provided conveniently forgets L.A.’s Museum of Contemporary Art, whose Geffen building alone provides almost the space of Fort Worth’s new home. (MOCA has 69,000 square feet of galleries, Fort Worth has 53,000.) Never mind. So much else is right that you can forgive the boast.

Bucking another grim museum trend, text does not run amok on gallery walls. Instead, this installation respects the primacy of sensual experience as integral to the power of art.

Some careful juxtapositions, such as a raging, red-orange 1989 Rothenberg between first-rate paintings from the 1970s by Philip Guston, are eloquent testimonials to artistic influence and thorny independence. Elsewhere, a mesmerizing conversation ensues among Vija Celmins’ atmospheric painting of stars in the night sky, a circle of stone shards on the floor by sculptor Richard Long and a magnificent 1969 seascape painting by Gerhard Richter, in which a breaking wave is strangely illuminated by light filtering through a rupture in the clouds above. These realist meditations on luminous air, earth and water dissolve -- like Ando’s building -- into evocative abstractions.

The inaugural exhibition focuses almost exclusively on the permanent collection, celebrating every museum’s primary function. Several important long-term loans, especially in the area of Abstract Expressionism, are also included, highlighted by Arshile Gorky’s masterpiece of organic abstraction, “The Plow and the Song.”

The installation is loosely chronological. The first floor starts with American art of the 1950s, then moves through Pop, Minimal and Post-Minimal art -- the last three being collection strengths. Work from the 1980s to the present is mostly installed upstairs.

Of 154 objects, fully one-third are new acquisitions. Chief curator Michael Auping has chosen well, although to my taste the collection is rather too closely attuned to the Manhattan establishment -- New York artists, followed by Germans. Call it Chelsea-centric. The emergence in the last 20 years of critical mass in art produced in Los Angeles and London is barely acknowledged, while neighboring Mexico and the Southern Hemisphere are omitted.

Texas artists turn up here and there, including such provocative emerging artists as Julie Bozzi (a tiny landscape painting that evokes huge, spooky spaces) and Eric Swenson (a sculpture of an imaginary breed of dog, impossibly balanced on point as a flaming red and black cape flies up behind him). Happily, space has also been found for regional work from the 1940s and 1950s by the Fort Worth Circle -- Bill Bomar, Cynthia Brants, Dickson Reeder and others -- since the museum was chartered as an art association in 1892, long before its current focus was established.

The Fort Worth Circle was typical of small groups of progressive artists who salved their sense of isolation in America’s grim provinces by banding together. The Modern Art Museum of Fort Worth has come a very long way since then. But it’s important to keep that historical memory alive, especially as some sense of anxiety still lingers: Concentrating on recent New York taste with an occasional Texas twang betrays a subtle ache for acceptance in established corridors of power.

It also makes the collection feel more conservative than it actually is. And speaking of anxiety: Almost half the inaugural show is tellingly composed of work that is gray, brooding or dusky -- from the monumental lead sculpture and clay-encrusted painting by Anselm Kiefer to the mound of poured acrylic foam by Lynda Benglis; from the brute typological photographs of water towers by Bernd and Hilla Becher to the acidic self-portrait death mask by Andy Warhol that greets you at the top of the grand staircase.

Ashen tones are encountered in room after room, suggesting a past half-century of gritty experience. Coupled with the gray concrete walls, dark granite floors and silvery aluminum panels on the exterior of Ando’s long, low building, the collection offers a museum of bleak beauty -- austere, refined yet tough as nails.

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Modern Art Museum of Fort Worth

Where: 3200 Darnell St., Fort Worth, Texas

When: Closed Mondays

Price: Free

Contact: (817) 738-9215; (866) 824-5566 (toll-free)