Swiss firm Herzog & de Meuron has unveiled its design for the expansion of the Miami Art Museum in Florida, US.

The proposed expansion at the 29-acre site will be three times larger than the existing structure.

The three-storey 120,000ft² green building will include large exhibition spaces, an educational complex with a library, auditorium, classrooms, workshop space, and a café and store.

The structure is placed on an elevated podium, under a broad canopy offering shade to the veranda and plazas.

The canopy will allow light to enter through its perforations and features a green garden.

The new building is expected to open in 2013.