Raynesway Construction was appointed by Fife Council to widen the A90 motorway to provide an additional lane to access a Park and Ride service. However there was a major problem, adjacent to the works was an existing embankment which could not be re-graded due to lack of space.

It was decided that the best solution was to install a concrete crib retaining wall to hold back the existing slope. Phi Group Ltd won the contract to design, supply and install its Anda-Crib retaining wall system.

Anda-Crib is a modular pre-cast concrete crib retaining wall system and has a design life in excess of 120 years that meets Highway Agency requirements. Anda-Crib can accommodate the demanding conditions required of structures by the highway, industrial and commercial sectors whilst maintaining an attractive appearance

This was the first Anda-Crib wall in Scotland, designed with double models to resist an excavated embankment of up 6.5 metres in height plus the surcharge from a 26º slope that extends over 10m in height from immediately behind the wall to the boundary. The Anda-Crib wall extends to a length of over 110 metres.

The wall was built around a special gantry foundation with the overhead information gantry in place adjacent to a live motorway. Special fibre optic cables to the rear of the wall also had to be taken into account during the works.

The project was completed in two stages to allow for on site changes to be adopted. The very limited amount of room for off-loading materials gave both the Phi and the Raynesway site personnel severe logistical problems to overcome. However, the project was completed within a 10 week programme.

Due to the nature, scale and location of the works Fife Council required a CAT 3 Design check, this was all included in the £150K project costs.