The Development Of Maccaferri’s Macres Reinforced Walling System With Steel Strip Reinforcing Elements

Of late there has been resurgence of interest, and in some quarters a preference to using steel inclusions as reinforcing elements in MSE (Mechanically Stabilised Earth) walls. An essential prerequisite for the effective introduction of any newly proposed system is to more accurately understand the pull-out resistance of the reinforcing elements and the specific nature of the reinforcement-soil interaction within the confines of prescribed select backfill requirements; an important concept fundamental to the design process. This paper originally presented at the 18th Southeast Asian Geotechnical Conference looks now at the strip development for Maccaferri Australia’s concrete panel and steel reinforcement retaining wall system, referred to as the MacRes System. It examines in detail the pull-out resistance of a newly developed steel strip as soil reinforcement in reinforced soil wall construction. The strip has indentations in an attempt to enhance the pull-out behavior. Large scale laboratory pull-out tests, using a pull-out box of 2 m in length, were conducted and the soil used was a silty sand from a borrow area. The testing program covered a wide range of overburden pressures from 15 to 120 kPa which enabled us to examine whether the calculated friction factor was dependent on the overburden pressure. Special dummy pull-out tests were conducted to correct the measured pull-out force and obtain the actual pull-out resistance. Independent consolidated drained triaxial tests, which measured dilatancy characteristics, were also conducted to characterize the properties of the tested soil.