A new lobby and sculpture terrace are among the final additions to a Los Angeles art museum that was strategically revamped over a 23-year period by local studio Michael Maltzan Architecture.

Located in the city's Westwood neighbourhood, the Hammer Museum is housed in a rectilinear, stone-clad building designed by American architect Edward Larrabee Barnes and completed in 1990. In recent years, the museum's programs have expanded to occupy space in an adjoining 1960s office tower.

The museum – which is part of the University of California, Los Angeles (UCLA) – was originally founded by the late industrialist Armand Hammer to showcase his personal collection of European and American art.

In 1999, a new director, Ann Philbin, who remains at the helm, set out to make the museum more accessible to a wider audience in terms of its artwork, programming and architectural design.

Local studio Michael Maltzan Architecture was tapped in 2000 to design a master plan for Barnes' building, consisting of galleries around a central courtyard. The museum had an insular feel, and the architects were tasked with making the building more welcoming.

With work being carried out over 20-plus years, Michael Maltzan said the project required "extraordinary persistence and inventiveness".

"This was truly a case of building the airplane while you were flying it," studio founder Michael Maltzan said. "I can't think of any other client that would have had the daring and imagination to carry it off."

Among the recent and final updates is a redesigned lobby, located on the ground floor of the adjoining tower, which was built in 1962 for Hammer's company, Occidental Petroleum. In 2015, the museum took over two floors of the tower.

The lobby has ramps, stairs and an elevator set around an elliptical information desk. Site-specific installations are planned for the space, and a labyrinth of red thread by Japanese artist Chiharu Shiota is currently on view.

The lobby's entrance is oriented toward the corner of Wilshire and Westwood boulevards, just across from a future stop for the LA Metro Purple line.

"A cylindrical, one-storey-high column set into a concave fold in the pavement marks the busy corner of Wilshire and Westwood," the team said.

"The column supports the edge of a porch that has been carved out of the tower to provide a dramatic and welcoming point of entry."

Beyond the new entrance and lobby, the team has added a new outdoor sculpture terrace, where one finds a towering bronze sculpture by American artist Sanford Biggers.

The team has also added a 5,600-square-foot (520-square-metre) gallery with a glazed wall facing Wilshire Boulevard, providing a connection to the streetscape.

The new additions are the latest in a long list of enhancements. The team has expanded offices and back-of-house areas; renovated galleries, a shop and a restaurant; and created a new gallery and study centre dedicated to works on paper.

Other changes include the creation of the Billy Wilder Theater, which was added in 2006 and features hot pink seats; and the construction of a pedestrian bridge that traverses the courtyard and connects third-floor galleries.

The entire project has cost $90 million (£72 million). The building has been officially dubbed the Lynda and Stewart Resnick Cultural Center — named in honour of the Resnick family, who donated $30 million to the Hammer Museum, its largest-ever single gift.

"From the start, our goal was to make the Hammer into a welcoming, public-facing, university-affiliated institution engaged with today's art and artists and the urgent issues of our time," said Philbin.

"I am beyond thrilled to welcome everyone to a reimagined Hammer Museum that is more than 20 years in the making."

Other projects by Michael Maltzan Architecture include LA's Ribbon of Light Bridge, which features multiple concrete arches that are lit from below, and a bright-white residential complex that contains over 60 studio apartments for formerly homeless tenants.

The photography is by Iwan Baan unless otherwise stated.

Project credits: 

Architect: Michael Maltzan Architecture, Inc
Design team: Michael Maltzan (design principal), Tim Williams (managing principal), Gee-ghid Tse (senior project designer), Nick McAdoo (project architect), Sahaja Aram, Dana Bauer, Emily Bidegain, Wil Carson, Joe DiMatteo, Wendi Gilbert, Tom Goffigon, Nora Gordon, Vano Haritunians, Ken Hasegawa, Sara Jacinto, Sevak Karabachian, Yong Kim, Yvonne Lau, Nick Martinez, John Murphey, Stacy Nakano, Edward Ogosta, Kyle Peterson,  Nadine Quirmbach, Kurt Sattler, Krista Scheib, Jeff Soler, Owen Tang, Hiroshi Tokumaru,  Nicole Tomasi, Jessica Tracey, Edward Tung, Yan Wang, Sharon Xu, Paul Stoelting
Graphics: Bruce Mau Design, Inc
Structural engineer: John A Martin & Associates
Structural design engineer: Guy Nordenson and Associates, LLP (John V Tunney Bridge)
MEP/FP engineer: ARUP, Innovative Engineering Group (BWT)
Lighting design: LAM Partners Inc, ARUP
General contractor: Matt Construction Corporation
Client: UCLA Hammer Museum
Museum leadership: Ann Philbin (director), Marcy Carsey (chair, board of directors)