Restek-UK Ltd are pleased to announce their first direct contract award from Network Rail for a bridge stabilisation project.
The bridge, a brick built double span structure which carries the single carriageway, over the railway (Altrincham to Mickle Trafford) line had experienced progressive deterioration following a burst water main, located beneath the footpath adjacent to the corner of the downside abutment.
This incident had adversely affected the integrity of the supporting ground and contributed to ongoing structural movement.
This was accompanied by a noticeable depression in the carriageway above, attributed to loss and weakening of backfill material beneath the abutment.
Network Rail sought technical advice to stabilise the bridge and surrounding wall structures and engaged Restek-UK Limited to provide a foundation stabilisation design and delivery of the approved works.
It was believed that the structural movement may have been the result of ground movement attributed to:
• Washout of fines in the silt, sand and gravel layers
• Softening and/or consolidation of the clay layers from movement of water. To inhibit further ground movement from the above mechanisms, Restek delivered ground treatment works, including:
• Permeation grouting in sand layers to increase their cohesion, density and replace the fines content that may have been lost and prevent further washout of fines within them. This also increased the inherent strength and stiffness of the granular layers and so improve the load bearing capacity beneath the footings.
• Compaction grouting in soft clays to densify any areas where softening may have occurred and similarly increase the stiffness and bearing capacity beneath the footings.
The stabilisation works were successfully delivered during night shift track possessions and included grouting to depths of between 1 to 7metres below ground level.
Restek-UK Ltd are currently in negotiations for a second project with Network Rail in the North West so watch this space for further news.
Please get in touch with [email protected] if you would like to know more about this project and our other remediation services.