WHEN BEAVER BRIDGES WAS AWARDED THE CONTRACT TO PROVIDE A REPLACEMENT BRIDGE STRUCTURE FOR AN EARLY 19TH CENTURY SUSPENSION BRIDGE NEAR FALKIRK, SCOTLAND THE LOGICAL AND OPERATIONAL CHALLENGE COULD NOT BE OVERLOOKED. HENRY BEAVER, A DIRECTOR AT THE COMPANY, DETAILS THE EXPERIENCE
There were very clear instructions for the latest bridge in Scotland that we were responsible for delivering. The new bridge for Falkirk was to be a 35m clear span structure that was 2.5m-wide, and 1.6m-high. It would have a 25m clear span ramp at one end and a semi spiral feature ramp at the other.
The main span was constructed from a 25m main section with a spliced connection at each end. This project is typical of the sort of abnormal indivisible load we are involved in. We manufacture, deliver and install all manner of steel and timber bridges for permanent and temporary use all over the UK and Europe. These can be modular in nature or long or wide but normally we do not breach standard C&U in gross vehicle weight.
Due to the complex and often non-linear nature of the projects we are involved in, we opted for some specialist transport equipment. Our prime mover is a STGO 6×2 tag axle Scania with a steerable rear axle. As far as we know there are only a handful of these in the UK and it really does make a difference.
Access to sites can be tricky and so all powered steered axles prove a real bonus, especially with a decent trailer man steering and watching from the rear. We mostly run our own transport just for our internal requirements as this gives us the ultimate in flexibility but we do turn to the wider heavy haulage industry and private escort firms from time to time depending on project and overall workload.
This particular bridge project required three loads of bridge and a 500-tonne Liebherr crane working at full ballast, This combination meant there was quite a logistical undertaking to get everything coordinated, into the right geographical area and access onto a tight site, which only had room for the crane and one truck at a time.
After a frantic period consisting of design check, procurement, fabrication, painting and non-slip coating of the bridge sections, the transport team were dispatched to Doncaster to load out from the paint shop. As anyone involved in the movement of finished high-value goods is aware, this process can be tricky and time-consuming to ensure that everything is just so, and that nothing is damaged or forgotten about. The trucks left in convoy heading for Glasgow services that night, ready for an early morning run in the next day.
The team set out early and accessed the staging area – a large municipal car park opposite the golf club and next to a large park – and set about preparing the bridge for installation.
This process involved hanging service ducts mounted to clips under the bridge, and checking the splice connections and carrying out any touchup painting to damage that might have occurred whilst in transit.
As this work was taking place, the mobile crane and ballast trucks arrived. Whyte’s crane hire was asked by the main contractor to provide its LTM-1500 8.1, and had the unenviable task of trying to thread this monster into a very small area and get rigged ready to receive the truck and bridge. The crane came with two ballast wagons in the form of Scania V8 6×4 units with crane ballast trailer grossing at about 100 tonnes each which carried the mats, winch, ballast, lifting tackle and the whole myriad of equipment needed to set up the crane ready for work.
MOVED INTO POSITION
This process took over five hours, which coincided neatly with the conclusion of the prep work on the bridge units. Shortly afterwards, the bridge team started bringing the bridge components down the road and then backing them into site and up to the crane.
The team slung the bridge units and packed them up on timber cribs to get them level and square to each other. Once this job was complete, the splice connection was effected and the main span was ready to lift.
On any lift, good and clear communication is key, and over a distance such as the one we were faced with, radios were the only way to keep things safe and efficient. After slinging the main span, it was carefully lifted out over the river and onto it’s new foundations.
The far access ramp was then backed into site and lifted straight from the transporter truck out over the whole of the main span and into position on the far bank. With near side spiral ramp still a few weeks away, it was time to start packing up the bridge team ready for the journey South with Whytes electing to leave things until the next day to de-rig the crane.