Underwater Patches For Steel Sheet Piling

Epoxy or metal patch

Mudline

Sheet Pile Cap System
Figure 5-19. Pressure grouting of steel sheet pile wall.

Installation of a concrete cap requires removal of the existing surface pavement or decking and excavation inboard of the sheet pile. When this has been accomplished, an inspection should be made to determine the condition of the tieback system and the need for replacement. If a new tieback system is installed (Section 5.6.4), care must be taken to electrically isolate the new tie rod from the existing sheet pile; otherwise, accelerated corrosion of the tie rod will occur.

Reinforcing steel is installed and forms are constructed outboard and inboard as necessary. Reinforcing should be welded to the existing sheet pile with steel spacers to maintain orientation. Shear lugs can also be welded to the sheet pile to help hold the concrete in place.

The outboard concrete face should be poured first and allowed to partially harden. The new cap and inboard concrete should be poured simultaneously. Allow the concrete to cure for 7 days before removing forms. Once set, the new concrete is cured then backfill and decking are replaced.

5.6.3 Replacement of Damaged Sheet Pile Wall

Where the existing steel sheet pile structure has been damaged to the point where patching or concrete facing would not be effective, a replacement wall may be necessary. The repair involves the use of heavy construction equipment and normally would not be done solely by UCT personnel. The procedure involves driving a new sheet pile either outboard or inboard of the existing structure as described in Table 5-16.

Before commencing construction, a survey should be conducted including a soils evaluation and diver inspection of the existing structural components: sheet pile wall, tie rods, and wale. This information will be used to conduct an engineering structural analysis to determine suitability of existing structure for the repair method.

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