The Salisbury Riverwalk is a 0.6 mile long walkway and bulkhead along the south fork of the Wicomico River in Salisbury, Maryland. Three bulkhead types exist on the Riverwalk. The earliest phase, designed in 1975, consists of steel sheeting and upper wood wale design. Other phases consist of steel sheeting and upper steel waler design or water level steel waler design. Various tieback systems were used.
The City first began to notice problems at locations along the Riverwalk around 2000. Repairs of the voids underneath the walkway were attempted in 2003. These repairs involved injecting foam in the voids. However, the quantity of foam injected quickly exceeded the estimated amount and injection was halted. When a section of the south side walkway cracked in 2005, a repair attempt uncovered a large void underneath the walkway. Continued evidence of voids and other structural concerns were noted, and the City of Salisbury hired George, Miles & Buhr, LLC (GMB) to investigate in June 2011.
GMB prepared a report which included:
• Evaluation of the sheeting, wales & tie rods, tie backs, and outfalls
• Repair recommendations & priorities
• Cost estimates & schedule for repairs
• Permitting requirements
GMB found the leading causes of voids below the walkway to be: loss of soil through outfalls, outward movement of the bulkhead due to excessive backfill, potential anchor slippage, wale failure, excessive hydrostatic pressure, and loss of fine soil particles through water migration under the sheeting. Other contributing factors include loss of soil through lifting holes in the sheeting, and overstress in the wales and tiebacks.
GMB prepared construction documents for the repairs, which are currently under construction.