FOUNDATION UNDERSCOUR REPAIRS

Marine Underpinning
Fabric Formwork Underpinning Bags are used to repair underscour voids to marine structures, bridges & harbour walls etc. Voids are infilled with mass micro concrete, providing

Structural support to underscoured areas
Good track record of successful underpinning
Good infill contact (Pressure head developed as the bag is filled)
Ease of filling, using Ready Mix or Site mixed grout or sand: cement micro concrete, with underpinning bags supplied divided into appropriate pour volumes as required
Longterm repair if future underscour is prevented (concrete mattress scour protection is often used where required)

The system is also reliably used on new structures see Foundations to Precast Structures

Procedure

Diver Survey - Survey voids after removing any soft deposits, typically recording void height, depth and length
Form Design - Manufacture underpin forms with typically 10% surplus to ensure good void infill
Mix Preparation - Prepare fluid and pumpable micro concrete as outlined on B65 and B66
Face Restraint - Fix face confinement to voids over 300 mm high
Position Forms - Fix underpin form into place
Pump Infill - Pump fill form with micro concrete
Remove Restraint - When concrete cured, remove temporary face restraint system

Proserve Provide
• Engineering Design of formwork and associated temporary works
• Bespoke fabric formwork units pre-fabricated to suit surveyed void size
• Installation guide document
• Installation support, with site visits if required

The customer often provides survey details of voids to be infilled. Any information available regarding the potential cause of the underscour (e.g. Shipping, current etc.) and river/ sea bed conditions is helpful in assessing future underscour risk, allowing us to advise accordingly.

Underpinning on Land
The system is also used on land and for difficult access areas, automated construction and wide foundations bearings etc.

Past Projects