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Spekeland Road Rail Freight Depot, site of
Spekeland Road, Edge Hill, Liverpool, UK
Spekeland Road Rail Freight Depot, site of
associated engineer
A.J. & J.D. Harris
date  1957
era  Modern  |  category  Building  |  reference  SJ370897
photo  courtesy Mark Whitby
The rail freight depot at Spekeland Road, Liverpool, was constructed to provide shelter with natural daylight to a four-track siding adjacent to the main line at Edge Hill. The constraints of post-war building material shortages challenged its designers, who produced a post-tensioned structure of slender concrete portal frames. The depot was in use for around 50 years but fell into disrepair and was demolished by 2015.
The technique of post-tensioning combines the strongest qualities of concrete and steel. The steel is in tension while the concrete is in compression. Rudimentary systems of post-tensioning, then called prestressing, had been pioneered from the 1880s. However, it was French engineer Eugène Freyssinet (1879-1962) who was at the forefront of prestressed concrete development (patent granted 1930). He realised that most of the damaging effects of concrete creep and relaxation under loading, which caused cracking, could be counteracted by the use of high-tensile steel tendons for the prestressing.
Freyssinet founded a company called Société Technique pour l'Utilisation de la Précontrainte to further develop his methods. He also granted licences to other companies. In the UK, these included: the Prestressed Concrete Company; a subsidiary of Mouchel with chief engineer Karl Mautner (1881-1949); and consulting engineer A.J. and J.D. Harris, set up by Alan Harris (1916-2000, knighted 1980) and his brother John Harris (1922-98). James Sutherland (1922-2013) joined the Harris practice in 1956 (known as Harris and Sutherland from 1964).
Alan Harris had worked with Freyssinet after 1945 in France, and he returned to Britain in 1949 to use the prestressing principle for UK projects. Post-tensioning had a particular advantage for a post-war construction industry beset by shortages — its strength meant viable structures could be built using less concrete and steel. Also, high-tensile steel wasn't rationed the way regular reinforcing steel was.
Post-tensioning was being used widely in the construction of bridges but by the 1950s, Britain needed industrial buildings. Spekeland Road Rail Freight Depot was one of those designed by Harris. Situated on the south side of the through Liverpool/Manchester main line, it enclosed four railway tracks and two line-level working areas. Its design was shaped by the austerity of the period, but also by Harris’ ability to visualise the structural forces at work and modify their actions using post-tensioning.
The shed spanned 31.25m, was 190m long and had a clear internal height of 6.1m at the eaves and 7.3m in the centre. The superstructure consisted of a row of 32 reinforced concrete frames over a concrete ground slab. The rail tracks entered at the east end and terminated at buffers under the west gable.
The portal frames were spaced at 6.1m centres, and provided lateral stability. Overall longitudinal stability was achieved through the use of a single pair of W-braces in the central bay, with individual bays linked to the bracing by precast gutter and sheeting rails bolted to the tops of the portal legs and forming edge parapets. A steel collar was bolted around the head of each leg to form a bracket under the precast concrete gutter, its intended purpose unknown.
Each frame was 1.82m in width (longitudinally in relation to the shed). Their legs tapered in section and vertical elevation, and supported an inverted T-beam spanning the shed. A knee brace was installed at each joint, supported on inclined ledges at the widest point of each leg. The knee braces consisted of diagonal members that fitted into sockets in the beam soffit. The braces were in compression, so no bolts or pegs were required. The legs tapered to pegs at ground level, forming pinned connections.
The portal beams were not supported directly by the legs — the only connections were the inclined post-tensioning cables running through the beams, which were anchored into the tops of the legs, and the knee braces. This arrangement made the portals into two-pin frames, though the inverted T-beams were almost shallow enough at midspan to form a three-pin structure. The stems of the Ts were expressed as external ribs.
The beams were erected on a rolling scaffold. Each was assembled from 11 precast segments, 2.8m long, minimising the craneage required. The 25mm joints between segments were filled with "1:1 earth-dry Portland cement mortar". Each piece of the inverted T had equal-sized flanges and a tapering vertical rib.
The flanges were 915mm wide and 40mm thick, with a single layer of reinforcement. Their edges were thickened to accommodate panels of patent glazing, and were stiffened at the ends of segments by transverse ribs on each soffit. The rib heights varied from 1.65m over the knee braces to 250mm at the centre, and the rib widths from 150mm at the eaves (excluding fanning out at the column connection) to 305mm at midspan.
The pegs in the base of each leg were packed rigid when erected and released to form hinges immediately before post-tensioning began, which was done as each frame was completed. Each beam had four post-tensioning cables threaded through its rib, and each leg had five cables running up its external side. The stressing sequence was: tension (i) the odd cable in the leg, (ii) the two in the beam, (iii) two in the leg, (iv) the remaining two in the beam, and (v) the last two in the leg. The applied force was 270kN. The tensioning lifted the beam off the scaffold, which could then be moved to the next bay.
The first and last frames were propped portals, differnt in design from the main frames and of heavier construction. Their beams consisted of nine precast 125mm thick panels separated by precast 100mm thick stiffening diaphragms, which supported gutter segments. The gutters ran across the top of the beams to form compression flanges. An in situ cast block was located at each end, anchoring the post-tensioning cables.
The precast legs were hinged at the base similarly to the other frames, but one leg of each end frame included a dummy fixed joint at the top, which also worked as hinges, intended to prevent compression forces developing in the thin webs and causing them to buckle. The depth of the end frame beams cleared the standard rolling-stock required height of 4.5m above th tracks.
The sides of the shed were open at the bottom, to a height of 2.3m, above which was asbestos-cement sheeting. The roof was glazed between portals, with glass covering 70 percent of its area. Each 4.27m wide run of patent glazing was formed from two inclined sets of panes meeting at a ridge, with the portal beams acted as the furrows.
Among the many uses for the depot was the handling of mail for the Royal Navy, and the trans-shipping of Guinness, molasses, scrap metal and other freight. It was also used as an engine shed and workshop. Commercial traffic apparently ceased in about 1996. However, localised cracking and spalling of the portal leg concrete was evident by 1992 and the cover to the reinforcement appeared to be around 10mm.
Between 2003 and 2007, a number of planning applications were made for various re-uses and the refurbishment of buildings on the wider site. Proposed uses included a waste transfer station, a vocational training centre, and a motorbike and quad biking centre. None of these came to fruition.
In March 2014, it was noted that though the depot’s portal frames were still standing, there was "no roof", cladding remained only along one side and "a large amount of vegetation" was growing in and around the building.
On 4th September 2014, Network Rail applied for planning permission to demolish all the buildings on their Spekeland Road site, including the former freight depot. Online examination of photographs show that demolition had been completed and the site cleared by 23rd May 2015.
Contractor: Norwest Construction, Liverpool
Research: ECPK
bibliography
"Concrete: Building Pathology" edited by Susan Macdonald, Blackwell Science Ltd, Oxford, 2003
"Obituary: Professor Sir Alan Harris 1916-2000" by Chris Burgoyne, Magazine of Concrete Research, Vol.53, Issue 2, pp.71-72, April 2001
"Liverpool Rail Freight Depot Revisit" by Frank Hawes and Mark Whitby, Concrete Quarterly, pp.22-25, Spring 1992
http://northgate.liverpool.gov.uk
www.freyssinet.com
www.vinciconstruction.co.uk
www-civ.eng.cam.ac.uk
reference sources   DNB
Location

Spekeland Road Rail Freight Depot, site of