Following a paper presented by the primary author at the 17th ICSMGE Conference in 2009, projects have been constructed using the concept presented on sandwich connection design for shored reinforced earth walls (SREW). SREW is a technology that combines the relative flexibility of a Mechanically Stabilized Earth (MSE) design in close proximity to an anchored or otherwise stabilized wall face with limited lateral space between. Rather than directly connecting the anchored wall face to the MSE section, a "Sandwich Connection" concept using overlapping reinforcements between the new wall fascia and existing stabilized face is employed. This paper presents case studies on three projects in the United States where the sandwich connection was used as a basis for design and construction. In two of the projects, connections were made to existing MSE walls where roadway widening was performed, and in a third project the connections were made to a conventional timber and H pile shored retaining wall. In all cases, the annular space between the existing and new retaining wall faces was less than 60% of the overall wall heights. The case studies will present several issues that were evaluated and resolved including selection and positioning of reinforcements and attachments, selection and installation of backfill, drainage, accommodating settlements and introducing seismic evaluations into design considerations using numerical modelling. A further finding in use of SREW near existing structures was the need to address extending upper reinforcing elements to prevent displacement and reflective cracking in the pavements supported by highway widening in the noted projects.
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