CLIENT CASE 1
FALKIRK SWING BRIDGE
BRIDGE DECK RENEWAL
Falkirk
Swing Bridge is located within the town of Falkirk and carries
the Scottish Central railway line over the Forth & Clyde
Canal between Carmuirs West Junction and Falkirk Grahamston.
The permanent way over the structure was provided by baseplates
screwed into longitudinal timber waybeams but over the years
problems with track gauge spread and derailments required that
improvement works to the permanent way construction be effected.
Following
an extensive design process it was decided that a load bearing
timber bridge deck would be installed onto which ballasted track
would then be laid. The repair scheme firstly required modifications
to be carried out to the existing steel superstructure in order
that the structure could accept the new deck timbers. These
enabling works were carried out during a series of track possessions
in advance of the main redecking operation. The redecking works
would be carried out during a 54 hour possession together with
p-way / waybeam removal, deck waterproofing and p-way relaying.
The
production of site sizes collected by the scheme designer, allowed
the new deck timbers to be manufactured from greenheart hardwood
timber to the exact sizes required to fit the structure, including
notches to accommodate web stiffeners, curved sections to match
perimeter beams etc. The availability of accurate survey information
also allowed the timbers to be predrilled at the proposed fixing
bolt locations in order to reduce site installation time.
CK
Contracts Ltd were contracted by First Engineering Ltd to install
the new hardwood timber deck which was scheduled to take place
during a weekend track possession. On receipt of the new hardwood
timbers from the sawmill, CK Contract Ltd carried out a successful
pre-works trial erection of the complete timber deck to prove
the fit prior to commencement of the site works.
Following
removal of the existing permanent way, timber waybeams and walkway
timbers, a steelwork contractor plated the top flange of the
longitudinal rail bearer beams to raise them level with pre-installed
ledge angles down either cess both of which would ultimately
support the new deck.
The
new deck timbers were individually numbered and grouped according
to their location on the bridge. The timbers were delivered
to the site by articulated lorries and transported to the bridge
alongside the Forth and Clyde Canal via a purpose built steel
trackway road. A 35T site crane was positioned at the end of
the trackway road to transfer the timbers directly form the
lorries onto the bridge ready for installation.
Installation
of the timbers was carried out manually with each timber being
positioned in accordance with the scheme plan by 6 men using
3 sets of log gabs. Each timber was secured using zinc plated
steel ‘L’ bolts which were fitted through pre-drilled
/ countersunk holes onto the underside of the steelwork flanges
and tightened using socket spanners. The complete deck was successfully
installed during a 12 hour shift ready for a Wolfin IB waterproofing
system to be overlaid.
Following the waterproofing operation, ballasted track was installed
over the bridge deck incorporating steel sleepers and guard
rails allowing the complete project to be returned ahead of
possession.
------------------------------------------------------------------------------------
CLIENT CASES...
