On the road to success
Grantham Southern Relief Road is a £100m scheme linking the A1 to the A52, crossing the Witham Valley and spanning a distance of 3.5km.
We worked on two separate phases of the project; the first being sheet piling works to facilitate underpass and culvert construction. Stitch drilling using the ‘Front of Wall’ system was necessary due to the presence of strong limestone: the drill casing and auger are simultaneously rotated in opposite directions by two rotary drives to produce the drilling action. Following stitch-drilling, we installed 88nr pairs of Arcelor AZ26-700s at 12 metres in length from Ivor King’s extensive stock of steel sheet piles, using our powerful RTG RG21T Telescopic Leader Rig.
All installation (and later partial extraction) was scheduled and carried out during several night shifts to minimise disruption to the adjacent A1 Great North Trunk Road, likewise deliveries made by Ivor King Transport.
We later returned to the scheme to facilitate building of a new temporary access bridge crossing the River Witham, directly adjacent to an existing viaduct for the East Coast Main Line.
A truly multi-disciplined approach
Our work was delivered through a variety of installation techniques to overcome various challenges of the job, including vibro-piling, impact driving, Giken Supercrush (silent and vibration-free
piling), CFA (Continuous Flighted Auger), mini-piling and conventional piling (using piling gates) to install a combination of steel sheet piles, universal columns and CFA bearing piles.
Mini-Piling was carried out using a Klemm 709 Rig with a 6 metre wide platform to install Ø450mm diameter bearing piles to a depth of 14 metres to support the temporary access bridge structure crossing the River Witham. This type of rig was deployed due to restricted site access being via the arches of an existing railway viaduct.
An element of conventional piling using piling gates was required with sheet piles being installed by means of crane suspended vibratory and impact hammers. This method of installation was deployed in order to achieve design toe level. Universal columns were also installed in this area, facilitated by use of a crane reaching out across the River Witham. Note that this part of the site was sandwiched between the river and the ECML, therefore this element of our installation was crucial to plant access, itself being dependent on construction of a temporary bridge, supported by our piling works.
Our Giken Silent Piler was used to install sheet piles vibration-free due to the close proximity of the railway viaduct carrying the East Coast Main Line which needed to remain open and unrestricted. Starter piles were installed using an excavator mounted Movax attachment with height and slew restrictors fitted to the excavator applied whilst working around the bridge for added safety.