Closure to 'Field Observations and Analysis of the Subgrade Response Beneath GRCS Embankments at the Council Bluffs Interchange System' by Aaron P. Gallant, Ehab Shatnawi, and Danilo Botero-Lopez

摘要

The writers appreciate the discusser's interest in the topic and for the opportunity to expand on one of the writers' main findings inferred from the subsurface extensometer measurements beneath geosynthetic-reinforced column-supported (GRCS) embankments. Aside from arching and engagement of geosynthetic reinforcement, load transfer below the column head due to downdrag can appreciably reduce stress imparted on softer foundation soils at depth, which in turn reduces differential settlement between the columns. The discusser has noted a minor error in the text of the original paper after presentation of Eq. (1), where Fig. 2(b) was referenced in the discussion of the stress carried by the geosynthetic and native material (Parts B + C). It should have been Fig. 2(a). Additionally, the discusser has raised relevant points related to the structural capacity of the column, which were not explicitly addressed in the original paper. These include installation effects, drag load, and position of the neutral plane.