Edinburgh’s Royal Museum has a long history of change. Its east wing opened in 1866 followed by the west wing in 1890. These were joined by a bolt on extension at the back in 1920 and the Darwin building in the late 1960s.
Today, 150 years on from its birth, a walk through its temporarily-closed galleries reveals a vast spiderweb of steel falsework, signalling the presence of major refurbishment work to give the museum a new lease of life.
“Access and layout was obviously a problem for the museum that it had to resolve.”
Alastair Moore, senior project manager, Balfour Beatty
One of the biggest changes − and consequently one of the grandest construction challenges − is that the main entrance at the top of a long, uneven set of steps will be superseded by two new street level entrances on either side. These will lead into a new foyer space which was once used as a storage basement − although in reality this is only a little above street level.
“[Access and layout] was obviously a problem for the museum that it needed to resolve,” says Balfour Beatty Construction senior project manager Alastair Moore. His team is carrying out the intricate £24.8M redevelopment contract for client National Museums of Scotland to a design by Gareth Hoskins Architects.
The old storage area is where a lot of attention is being directed. The masonry walls and barrelvaulted ceiling will become an obvious backdrop for a grand new entrance hall with café area.
Starting from the bottom
However, before the cosmetic work could take place, the first task was to excavate 1.4m down to make the floor level inside marry up with that of the street.
But more structural changes were needed to open up the space. This involved removing the spine wall running along the middle of the basement, parallel with the museum front.
The contractor replaced the wall with a series of steel columns supporting 4m to 8m long beams. The columns are spaced to open up the basement area, freeing up the area once occupied by the wall.
This is where some of the vast amount of temporary works have been needed − an aspect of the project that Moore says is “unique and potentially fraught with problems”.
Balfour Beatty’s temporary works office in London worked closely with structural engineer David Narro Associates to create the intricate design for this complex work.
One of the principal requirements was to create a strong system of supports for the barrel vaults while the team removed the spine walls which is divided into nine sections.
To do this, Balfour Beatty’s site workers first excavated down around the base of the spine wall to lay a 700mm to 1m deep sacrificial concrete load transfer base. They then installed a series of RMD Kwikform raking shore props to form A-frames on either side of the section of wall they were to demolish, ensuring that no two adjacent sections were worked on at once.
Site workers then excavated between the props to make space for installing 2m2 reinforced concrete foundations for the permanent steel support columns and beams.
The beams are between 4m and 8m long and have become known as coffin beams because of their shape in section. Once in place, the beams were preloaded with jacks to enable the temporary props to be removed.
Demolition work moved painstakingly forward, with temporary supports removed and reassembled after each section of wall was demolished.
Once in place, stone masons began the intricate task of taking down the 800mm to 1m thick wall.
An intricate process
The process was made more intricate by the building’s Grade A listed status, which meant each stone had to be removed by hand and reused elsewhere in the museum’s reconstruction.
To create the new access points at the front of the building, just a few metres away, the site team has also been forming two, 11m wide openings in the basement walls at ground level.
Again, the operation has involved creating substantial temporary supports − so that site workers could cut openings out of the walls for the new doorways.
The contractor drilled 15 cores above the locations of the new access points to take steel needles which will support the stonework above the openings.
What should have been a relatively simple job was complicated by the presence of heavy ironwork within the stone.
Grinding through the metal was laborious, but eventually apertures were created for each of the 15 needles, which weigh almost 1t apiece.
Once in place, RMD’s heavy duty Megashor props supported the steel needles on the external and internal sides of the wall.
More preloading was required to ensure the temporary support could take the strain during the subsequent removal of the masonry to create the doorways.
Removal of the masonry wall made way for the installation of the permanent steelwork for each entrance.
When this was in place, site workers removed the steel needles and props before the core holes were permanently infilled with brick and dry packed.
“The project’s temporary works have been unique and potentially fraught with problems.”
Alastair Moore, Balfour Beatty
Beyond the grand new entrance hall, Balfour Beatty Construction − along with additional RMD support systems − is carrying out yet more reconstruction work to improve the museum’s use of space and aid the flow of people from gallery to gallery.
As a result, it is installing two new insitu concrete staircases from basement to ground floor − requiring the creation of new holes in the ceiling above the basement − and creating openings for new escalators on two higher floors.
In addition, in a separate gallery space, the team had to remove an atrium to drop in new permanent 16m to 17m long steel beams to create a loading bay with the help of a spider crane.
Work began on site in September 2008 and reconstruction set to finish in December 2010 ready for the new-look gallery to open in 2011.
The east wing and one third of the main hall were opened by Prince Albert in 1866, by which time it had become the Edinburgh Museum of Science and Art.
Prince Albert was a driving force behind Britain’s 19th century museum movement and it is significant that he laid the building’s foundation stone in 1861 − his last public act.
Since it opened in 1866, the museum has seen many changes in its architecture and its identity. Fowke’s vision took 30 years to complete, culminating in the opening of the west wing in 1890.
Behind the Chambers Street facade, the museum has been altered, adapted and extended in response to the growth in the collections and changing public use.
The Royal Museum Project is a £46M initiative to transform and update the museum which forms part of the National Museums Scotland arts organisation.
Work has been funded by awards totalling £34M from the Heritage Lottery Fund and the Scottish government while over £9M has been raised from private sources to fund the transformation.
When it reopens in 2011 the museum aims to reveal collections in new and dynamic ways within 16 new galleries, a spacious special exhibitions gallery, a state-of-the-art Learning Hub, Information Zone, new social spaces and glass lifts and escalators to the upper galleries.