Over a nine day rail closure, Story Contracting on behalf of Network Rail, successfully delivered upgrade works on the River Avon viaduct.
River Avon is a 200m 9 span single line viaduct sat in the middle of a flood plain, which is mainly underwater for five to six months of the year. It is being converted to allow for future twin tracking of the viaduct and section of the line, which will improve passenger and freight service on the important railway corridor through the West Midlands.
The viaduct consists of two bridges sandwiched together, with the original bridge built in the 1840s and a second bridge added alongside the structure in circa 1870 to create LSC2/4 however, they work independently of the other.
The team successfully delivered all planned works during the closure, plus an additional 26no of units on the redundant section when the core works were completed 24 hours ahead of programme. Works included the removal of the existing rail in panel sections using the McCulloch panel lifters.
The viaduct was dug to a total dig depth of 575mm over the 200m viaduct, and then a further 90m dig over the tie in sections, removing a total spoil quantity of 2200T from the site via various methods on the tight single line.
Once down at dig depth, Story along with colleagues from Story Plant, installed 84 new downside pre cast units and waterproofed along the length of the viaduct in readiness for the installation of the new ballast and track, which is going back in again using the panel lifters.
With a peak track lift of 330mm, a total infill volume of 2000T has gone back in over the bridge.
Whilst undertaking all of the core works, Story have also continued to work 24/7 to infill the first span, a 18m by 9m arch, which was a late design change required to complete the works. This was due to excessive movement and flattening of the arch barrel, which will allow for the structure to be bought back up to the full assessment using a series of monitoring provided through Meta to give live monitoring of the operational railway.
So far we have installed 32no of sheet piles at up to 14m depths, with over 20 Ischebeck anchors going in to tie back the piles and into the abutment walls in an effort to stabilise the structure, all whilst Span 1 was excavated allowing for the client to keep an operational railway functioning.
The team have then gone on to install 28no of 15.5m 450mm diameter SFA piles in partnership with Van Elle to allow for a 126m3 concrete slab to be placed as well as the infill.