Freyssinet, the structural repair contractor, has successfully trialled the world’s first masonry arch lift, with funding from the RSSB Avoidance of Bridge Reconstruction Competition.
The ElevArch masonry arch jacking trial saw the bridge arch raised 900mm vertically over a six hour period before being lowered to 450mm above the original position with the gap in the abutment filled to restore permanent support.
The world’s first bridge lift of its kind, used a patented technique which involved cutting the masonry arch free from its abutments and wing walls and jacking it upwards to enlarge the space below. As the jacks lifted, hardwood timber crib stacks were inserted beneath to support the bridge before the gaps were filled with concrete to restore permanent support to the arch. The road embankments approaching the bridge were raised to adjust to the new bridge height.
The trial held in October at Moco Farm Bridge was on a section being recommissioned on the East-West route between Bicester and Bletchley.
Launched in February 2014, the competition was devised to find an alternative to the demolition of overbridges when electrification or larger rolling stock has to be accommodated on the railway.
With a growing emphasis on electrification, the ElevArch innovation could prove a cost effective alternative for Network Rail in the future.