Question
How do I model a geogrid in LimitState:GEO?
Solution
A geogrid can be modelled in LimitState:GEO by applying a suitable Engineered Element material to a boundary.
To specify a geogrid material you only need to set a suitable pullout factor (Tq) and a small lateral factor (Nc). The latter needs to be small but finite (of the order 0.01) in order to stop the geogrid from ‘floating away’ in the analysis. All other ‘factors’ can be set to zero. The moment of resistance can also be set to zero and the tensile / compressive strengths set to 1e+30 (effectively infinity) unless the actual values are known.
Attached is a ZIP file containing a brief document and a LimitState:GEO file which detail the analysis of an embankment containing geogrid reinforcement layers. More information on Engineered Elements is also available in the LimitState:GEO User Guide.