The Tacoma Art Museum broke ground Thursday on a $15.5 million building expansion and new galleries to exhibit the top-tier Western art collection of German billionaires Erivan and Helga Haub.

A 16,000-square-foot new wing is underway by Seattle-based architect Tom Kundig of Olson Kundig Architects. The expansion will house 280 works by noted Western artists and comes with a gift of $20 million from the Haubs.

“This collection ranks among those of the highest breadth and caliber in American museums today,” said Peter H. Hassrick, retired museum director, curator, and American and Western art scholar. “Western art as a genre has added much to the overall development of American art over the past 150 years. The Haub collection represents a remarkable esthetic contribution as well as a fascinating historical narrative.”

Hassrick advised both the Haubs and Tacoma Art Museum on shaping the gift of art, building funds, and endowment support.

Among the outstanding works that the Haubs collected since 1984 are works by significant historic Western painters, such as grand manner landscape painters Albert Bierstadt and Thomas Moran; titans of Western genre, Frederic Remington and Charles Russell; as well as works by artists such as E. Martin Hennings and Ernest Blumenschein. The collection also contains works by notable modernist painters, including Georgia O’Keeffe, as well as more contemporary artists such as John Clymer, Tom Lovell, Bill Schenck, and Clyde Aspevig. The works range in date from the 1820s to the present.

Erivan Haub is the head of a family-run international conglomerate, The Tengelmann Group. While the Haubs were based in Germany, they kept homes in the Tacoma area and raised their three sons there each summer.

Son Christian Haub told The News Tribune that the family chose Tacoma Art Museum to hold the collection because they wanted the artwork to stay together, they had local ties, and the museum's director, Stephaine Stebich, speaks fluent German.

The expansion is expected to be completed by fall 2014, making it the most significant public holding of Western artworks in the Pacific Northwest.