Paisley Gilmour Street Railway Station Canopy Renewal Canopy ...

Paisley Gilmour Street Railway Station Canopy Renewal
Contents
Canopy Renewal
GILMOUR STREET STATION, PAISLEY.
1. Station description
2. Brief history
3. Canopy
4. Proposal
5. Detail of proposal design and materials
5.1. Glazing
5.2. Foundations and substructure
5.3. Superstructure
5.4. Painting scheme
5.5. Roof access
5.6. Roof access system
5.7. Drainage
Acknowledgements:
This report was prepared with the assistance of documentation provided by
WYG and gm+ad architects.
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Paisley Gilmour Street Railway Station Canopy Renewal
Paisley Gilmour Street – Canopy Renewal Proposal.
1. Station Description.
Paisley Gilmour Street is a busy railway station carrying approximately 12,000
passengers daily.The Station is also an important transport interchange for
other local destinations including Glasgow Airport, Paisley town centre,
Braehead Shopping Centre, St Mirren Football Club and Hillington Industrial
Estate.
Paisley Gilmour Street is a Grade B Listed Railway Station. The Station
building comprises three levels of which the topmost (2nd floor) is platform/
station level. The lower floors are generally tenanted units in use as shops
with access to the Station available at ground/ street level from Old Sneddon
Street and County Square. Platform 1 is located adjacent to the north
boundary. Platform 4 is located adjacent to the south boundary. Platform’s 2
and 3 are set on a centrally located island. Gilmour Street Bridge is located
towards the east end of the station.
The existing roof canopy structure consists of a series of main and
intermediate metallic lattice girders supported on cast iron support columns.
There is a profiled valance with polycarbonate roofing. The three canopies at
the Station are in a state of disrepair and will be the focus of this Listed
Building Consent application.
2. Brief History.
The Application Documentation provides a thorough insight into the historic
development of the Station. This report refers to the history in so far as it
relates to the development of the Station canopies.
The Station was opened on 14 July 1840 on the Glasgow, Paisley,
Kilmarnock and Ayr Railway. At this time Paisley Gilmour Street Station
possessed only two through platforms and no roof canopy, with the tracks
diverging at the west end of the station as currently to direct services towards
Ayr and Gourock.
The Station was expanded in 1883 as part of the improvements to the
Glasgow and Paisley Joint line to include four platforms and it is believed that
the first roof canopies were erected at the station around that time. The early
canopy roof was a hipped-end multi-ridged roof with transverse gutters
located on the main lattice girders, ridges running from North to South across
the platforms. The track was not covered.
The station was electrified as part of the 1967 Inverclyde Line improvements.
It is believed that around this time the roof cladding was also changed to the
existing arrangement of steel and translucent sheeting panels supported on
steel purlins.
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Paisley Gilmour Street Railway Station Canopy Renewal
3. Canopy.
There are three canopies covering the platform area. The existing roof canopy
framework structure is approximately 150m long and 38m wide and consists
of a series of 17 main and intermediate metallic lattice girders. The main
transverse lattice girders are supported centrally on cast iron columns
founded within the platforms and upon masonry corbels within the north and
south station boundary walls. The canopies on platform 1 and 4 consists of a
mono-pitch structure. The canopy covering the island platform 2 and 3 is a
inverse low pitched roof. The materials are translucent fibre composite panels
forming the top with grey panel valances. The canopies are shaped slightly to
follow the bowing shape of the platforms.
4. Proposal.
The existing roof structure is dilapidated and requires replacement. Our
proposals will entirely remove the existing roof canopies from the Station. A
new single roof canopy will be created covering from boundary to boundary
across the majority of platforms 1 to 4. Running to approximately 150 metres
long the design will reflect the original with glazing, hipped-end, multi-ridged
roof with transverse gutters located on the main lattice girders, ridges running
from North to South across the platforms however the current proposal runs
across the tracks to create a single roof structure for the Station. The existing
lattice metalwork superstructure and cast iron support columns are retained in
the design.
The existing roof canopy structure is proposed to be renewed. This includes
the following works:
Replacing the entire roof cladding and secondary steelwork with a
transverse single glazed multi-pitched roof spanning between the main
lattice girders, encompassing both the platforms and track areas.
The new roof will be approximately 40% greater in plan area than the
existing as areas occupied by the tracks shall be covered and therefore
the existing lattice roof structure will be strengthened to cater for the
additional loads.
New drainage will be installed which will direct flows to the existing
outfalls at both the north and south sides of the station.
A new roof access system will be provided to the roof. Access to the
new system will be from staircases/ladders on platform 1.
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Paisley Gilmour Street Railway Station Canopy Renewal
5. Details of proposal design and materials.
5.1. Glazing.
The roof glazing system consists of 6.4mm laminated planar glass supported
and restrained by PL6 glazing bars and supported by steel purlins which span
between new steel pitched roof beams.
5.2. Foundations and substructure.
It is anticipated that existing column foundations which are supported on fill
between the retaining walls of the original station will require strengthening.
The form of strengthening is envisaged to be enlargement of the existing pad
foundations using dowels and reinforced concrete to reduce bearing
pressures on the substructures.
5.3. Superstructure.
The existing lattice girders will be strengthened using the following
techniques:
Additional flange plates will be bolted to the soffit of the main lattice girders
in order to enhance the bending capacity of the girders.
The main lattice girder web members will be strengthened by the addition
of angles or channels to the end members in order to carry the shear
forces from the end of the beam down to the supports.
The main strengthening works involve the addition of a rolled steel beam
section above the main lattice girders in order to significantly increase the
section depth. The beam will be bolted at approximately 150mm centres to
the top flange of the girder in order to provide a longitudinal shear
connection. The soffit of the proposed rolled steel section will be notched
over the locations where the OHLE supports are positioned above the top
flange of the lattice girders.
The rolled steel beams will act as valley girders and will accept the main
pitched roof beam sections. The roof beams will be tied in order to limit
lateral loading effects on the existing lattices during construction.
The existing columns have been found to be inadequate to resist wind
loading effects and therefore horizontal plan bracing will be introduced in
the end bays in order to carry the loads back to the main masonry
supporting walls. These loads will be distributed along the length of the
wall by longitudinal beams positioned just in front of the masonry walls.
Additional longitudinal beams will be included along platform 2/3 above the
existing bow tie members in order the distribute loads down the length of
the station.
The roof is joined to the wall of the building with lead capping to the
cornice and blocking course to parapet. This is detailed in drawing
A057311-31-A-301.
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Paisley Gilmour Street Railway Station Canopy Renewal
5.4. Painting scheme.
The existing cast iron columns will be predominantly blast cleaned (except for
capitals) and repainted with an M24 paint system tested in accordance with
NR/L3/CIV/040 Issue 1 to give a design life of 25 years. Refer to drawing
A057311-31-R-122 contained within Appendix B.
It is traditional for the Station to be painted in the livery colours of the
operating company; this has seen paisley Gilmour Street change colours from
several times in the past. Given the extent of the works at Paisley Gilmour
Street it is considered this is an appropriate time to re-brand the Station with
the Saltire livery. This means a change from carmine and cream to blue, grey
and white. We have provided details on the proposed appearance in the
application pack. External steelwork will be matt finish which will prevent a
reflective appearance.
5.5. Roof access points.
Two new roof accesses will be created by the project. Refer to drawing
A057311-31-A-304 and 305 for details.
The first will be a simple steel staircase provided on Platform 1 in the area
between the existing platform buildings. The metal stair will be constructed
within a new enclosure formed at platform level, replicating the façade of
the existing masonry and decorative Victorian timber screen frontage of
the platform buildings on either side of the gap. A mesh screen extending
to roof level will be provided above the fascia line of the enclosure. This
will ensure security and to limit the impact of any falling objects by those
using the stair.
Emergency escape companionway ladders will be provided within the
existing ‘kiosk’ building at the east end of Platform 1. A matching mesh
screen extending the access point at roof level will be provided above the
fascia line.
5.6. Roof Access system.
A bespoke roof access system designed in association with The Clow Group
Ltd. is proposed in all areas of the roof. This has been used elsewhere
including the Glasgow Central Station Roof and has successfully been
accepted for use at Edinburgh Waverley. The proposed system consists of
mobile safety cages which run along tracks on both the north and south sides
of the roof and down each of the valleys. In addition, the hip ended multiridged
roofs are accessed by a travelling inverted ‘V’ gantry sliding on the
integral walkway tracks. Gutter walkways are 600mm wide aluminium open
tread format, hinged to facilitate cleaning of the gutters and gutter outlets
below. The walkways are supported on galvanised metal ‘T’ section straps
mechanically fixed to the bottom glazing purlin. Mobile safety cages are
provided with ‘pockets’ and straps for transporting replacement glass panels.
The length of the safety cage permits two operatives to move safely along the
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Paisley Gilmour Street Railway Station Canopy Renewal
gutters simultaneously. The system is constructed from mill finish aluminium
this will have a dull grey appearance.
5.7. Drainage.
The new roof will be drained via a series of valley gutters to carrier pipes
running along the northern and southern facades below the lattice girders.
Additional gutters will be provided to drain the hipped ends of the roof along
the facades. The system will be a conventional gravity system.
New outfall pipes will be installed at each end of the northern façade on Old
Sneddon Street which will direct flows to existing combined sewer pipes
located within the roadway. A replacement outfall within the station car park
located to the southwest corner of the station is proposed.
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