Rotary Bored Piling Specialists

Bristol Finzel’s Reach



Ultimate Client
-
Main Contractor
Andrew Scott
Type of Piling
Bearing & Friction
Diameter
750mm/1050mm
Depth
18m
Project Difficulties and Restrictions

Piles were required to be installed in an existing dock to provide foundations for abutments and piers to a new link bridge providing pedestrian access for a new development site.

 

The original scheme was for multiple mini piles installed from within sealed cofferdams.  The space restriction limited the size of available pile diameter, and this severely limited the horizontal load capacity of the foundation.

 

Access to the site was only available by barge, from a landing station half a mile upstream from the site, under several low lying bridges.
 

The Martello Solution

Martello proposed a solution to replace the multiple mini piles with 750mm diameter piles using the technique developed at Leeds Station, and thereby negating the necessity to install cofferdams prior to piling.

 

Initially a 900mm diameter Caisson was installed by the rig through the dock and into the underlying firm material, then 750mm diameter casings were installed through any unstable material and the pile bored to its founding depth.
The reinforcing cage (full depth) incorporated a permanent thin-gauge steel liner attached to the top of the cage to provide a shutter to contain the concrete and lift the concrete up, and out through the water.  
This technique allowed the contractor to save programme time, and make use of the completed pile to provide a support system for his following temporary works to form the concrete piers.
 

Specific Project Features

The dock is located in a fashionable part of Bristol and noise restrictions would apply to the project, restricting the use of heavy hammer driving equipment.

The 14 No 750mm diameter piles were installed by Martello, using the MP5000 series rig working off a barge, with the piles bored to 17.0m with the concrete finishing approximately 1.5m above dock water level.
The piles were completed on programme in this second application, using the system developed by Martello for forming large diameter piles through water.
 

Future Potential

This technique has the potential to be used wherever it may not be possible to pre-drive permanent steel casings.
The liner to the pile also has the potential for the addition of a welded (Sheet Pile Clutch) for possible integration with a sheet piling system.
 




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For more information about our services and how we can help you with your projects, please call us on 01476 570781 or leave us a message below.