Figure 50. Low-height, i'ree-sLaiidiiig aluminum bulkhead 



(Courtesy of Kaiser Aluminum & Chemical Sales, Inc.). 



carefuUy against the section modulus to make sure the sheets will not be overloaded. The 

 sheets are brittle and should only be used where they can be jetted into place. Some 

 cements in asbestos-board tend to deteriorate after long periods of immersion; therefore, 

 only sheets that are certified by the manufacturer for marine applications should be used. 



Where the exposed face is more than about 6 feet in height, the section modulus 

 provided by the lightweight sheets is usually insufficient to resist the active soil pressures, 

 and careful engineering analysis is required to determine design limits. Some of the heavy 

 gage steels may prove satisfactory to about 8 feet of exposed wall, but beyond that, a 

 stronger section is needed. Standard rolled steel sections are generally used for steel 

 sheet-pile walls with an exposed face more than 8 feet high. These walls can be designed as 

 freestanding or cantilever-type structures, if the space just behind the wall is required to be 

 kept free of any obstructions such as a tieback system. The extra pile length for such 

 construction is usually costly, however, and tiebacks with either a single or multiple-wale 

 system are more economical. Detailed engineering analysis of the soil mechanics involved 

 and structural analysis of the steel sections used will ensure a safe and most economical 

 design. 



96 



