Santon Road bridge replacement, UK
ALE were tasked with the installation of a new bridge, weighing 300t, at Santon Road. This is the first time ALE installed a bridge by using SPTs and turntables to rotate the decks.
Prior to the execution, the trailers were set up and the new bridge sections were weighed, with each individual deck weighing approximately 150t.
In order to perform this bridge replacement ALE were required to develop an innovative solution to install the new bridge in a restricted area. They devised a method using turntables positioned on SPTs to lift and rotate the individual bridge decks.
Firstly, ALE lifted the two bridge decks and positioned the SPTs in a 2 file, 10 axle line SPT configuration underneath the bridge decks. ALE had already pre-determined that the using of a 2 file SPMT instead would not be stable because of the slope and height, deciding that the 2 x 10 row SPTs would be used.
Once the bridge decks had been lifted clear of the trestling by the SPT trailers the deck unit was rotated approximately 90 degrees utilising the turntable positioned on the SPT trailer and a hydraulic power pack powered by two hydraulic rams attached to the turntable. The bridge deck was then secured to the trailer and then driven to down to the exiting bridge.
Once the tractor and trailer unit was positioned in front of the existing bridge the trailer was secured and additional stools placed under the trailer for extra stability as the bridge deck was rotated 90 degrees ready for installation. The process was repeated for the second deck although the second deck was not rotated until after the first deck had been installed.
ALE then had to wait until the existing bridge had been demolished before the new bridge could be installed during the possession. Once permission was given, ALE drove the rotated bridge deck forward, lined it up and lowered it down where checks were made on the line and level of the deck by the clients’ engineering team. This process was repeated for the second deck once it had been rotated. The whole bridge installation took place in three hours.
The trailers were then driven back to the site compound ready to be demobilised.
This is the first time ALE had attempted to transport heavy bridge decks by rotating them using SPTs and turntables.