19 June 2001
SR-10: INSTALLING A CONCRETE CAP/FACE ON A STEEL SHEET PILE
: Large-scale deterioration
of the steel sheet pile structure has occurred;
patches can not be used for repairs.
Description of Repairs: Excavate the soil from behind the wall to a level
required for the new concrete cap or attachment of form ties for a concrete face.
Remove all marine growth and deteriorated steel and clean surfaces. Two
methods are available for installing a concrete cap/face:
For Concrete Cap: Build forms, place reinforcing, and pour concrete at mean
low water. After curing, remove forms and backfill behind wall (see Figure 8-10).
For Concrete Face: Place and fasten blocking and low wale against existing
sheet piling. Drive the timber sheet pile wall about 300 mm (12 inches) in front of
existing sheet piling using wale as a guide. Attach outside wales to timber
sheeting and place concrete by pumping or tremie. Leave timber sheet piling in
place or remove as desired (see Figure 8-10).
For partial concrete facing of steel sheet pile wall, techniques exist to repair a
deteriorated wall from the exterior side without requiring excavating. One method
uses timber formwork (see Figure 8-10), welding steel studs to the steel sheet
pile at locations where the metal is sound. The shear lugs help to hold the
concrete in place. A temporary steel frame, which supports the timber formwork,
is suspended from the top and welded to the exterior of the wall above the
waterline. Blocking is used to maintain a 300-mm (12-inch) minimum space, and
reinforcing is placed in the center of the space. Concrete is placed by pumping or
tremie method. The form work can be removed within a few days.
Application: Used to restore structural strength at the top of the wall (cap) or
prevent further loss of soil through holes in the sheet piling (face). Does not
restore bending moment capacity in wall. Provides protection against further
Future Inspection Requirements: Annually inspect the sheet piling areas
immediately under the pile cap to ensure that further corrosive damage is not
being weakening the support for the concrete cap. Follow similar procedures for
partial concrete faces. For complete concrete facing, follow normal inspection