The was a maritime museum in Osaka, Japan. It was opened by the Mayor of Osaka City on 14 July 2000 having started on site in March 1998. Designed by architect Paul Andreu with engineering design by Arup and Tohata. the museum was built on reclaimed land in the Bay of Osaka at a cost of 12.8bn yen, with a replica Edo period trading ship, the Naniwa Maru as its centrepiece. The requirement of the dome to resist seismic, wave, and wind loads and its successful completion, led to the building winning a Structural Special Award in 2002 from the Institution of Structural Engineers, UK. The museum was closed on 10 March 2013 because of financial problems, and because the number of visitors had greatly reduced after the museum's initial popularity. Site and brief Osaka City wished to develop a museum that reflected the maritime history of the port city. They had planned for it to be placed on reclaimed land in Osaka Bay, where a number of office schemes and a convention centre had been built, to create a landmark building to draw people from the city centre. Upon approaching Paul Andreu he provided preliminary sketches showing a dome, and suggested that the museum should be placed in the water itself and so a 300,000 m² basin was to be excavated from the reclaimed land with a spherical dome seeming to float in the bay, accessed by a submerged tunnel. Design Andreu based the dome on a viviani's curve. Arup were responsible for the design of the structural, mechanical, electrical and seismic engineering solutions for the dome and internal structure holding the exhibits within, whilst Japanese firm Tohata were responsible for the engineering of the entrance building, the submerged tunnel and the dome substructure. With a site consisting of 25 m of reclaimed land on top of 15 m of alluvial clay, piles were designed to be 40 m long. To prevent the building sinking into the ground if an earthquake caused liquefaction of the ground, the top 10 m of the piles were designed as precast concrete piles with steel casings. In order to prevent the building from rising up due to buoyancy the piles were cast with a ground floor slab 1.6 – 2.5 m thick to provide sufficient weight. The semicircular landside building contained a ticket office, the entrance hall and administrative offices, with storage and