ANCHORED WALL DESIGN: COMPARING THE GLOBAL AND PARTIAL FACTORS OF SAFETY INCORPORATING THE AUSTRALIAN STANDARDS

A versatile and user-friendly model has been developed for evaluating the factor of safety of anchored sheet-pile structures, using both global factors of safety (GFS) and partial factors of safety (PFS) methods, abiding AS 4678 standard, an Australian standard for retaining wall design. The developed model is aimed to determine the following features: (i) depth of embedment, (ii) total wall height for determining the amount of material required, (iii) the length of anchor, (iv) the anchor force and (v) the maximum moment acting on the sheet-pile wall. Key findings are highlighted based on the design calculations. This study incorporates different design scenarios including layered soil, line loads and uniformly distributed surcharge loads to draw comparisons between the GFS and PFS methods. Many examples are used to validate the outputs of the program. The results indicate that the PFS method is preferred for design strength and safety aspects, whereas the GFS method is adopted for cost effectiveness and simplicity of design calculations. The limitations of the Australian standard AS 4678-2002 are discussed in order to identify the superiority of one method over another.