MSE SEGMENTAL BLOCK WALL SYSTEM IN A RIVERINE ENVIRONMENT

This article describes how mechanically stabilised earth (MSE) segmental block unit wall systems were used in the recent Rochester Flood Control Project in Rochester, MN, USA. It discusses: (1) how the process was selected from other alternatives; (2) the design of the MSE wall system; and (3) the segmental block units used in the structures. It also describes the costs and the method of construction. The method used to present the contract documents for bidding purposes is also described. The project was designed by the St. Paul District Corps of Engineers, and consisted of channel improvements and recreation features along three rivers. Six stages have been completed, and the other two will be constructed in 1994 and 1995. The segmental blocks were specified to provide concrete compressive strength of 4500psi, to ensure protection from freeze-thaw during the structures' design life. The actual bid price for the wall system was $19.60 per sq ft, including geogrid, segmental block units, geotextile, drainage fill, backfill, and fencing. The MSE wall system provided a cost-effective, highly aesthetic alternative to conventional concrete retaining walls for minimising the effects of flooding. Other advantages of the MSE wall system include: (1) flexible construction sequencing; (2) minimised dewatering costs; and (3) no need to use heavy construction equipment.