<p><p><h2>Preferred Design Procedure</h2>There is no standard FHWA design procedure for the use of Geotextile Encases Columns (GECs). Currently, three existing design procedures are used in practice: a unit cell analytical model, a numerical method, and a method based on bearing capacity and predicted settlement.</p><p>See the <em>Design Guidance</em> document for column supported embankments for recommended design procedures for the arching/load transfer mechanism from the embankment to the columns.</p><p>Table 1 at the end of this document lists typical inputs and outputs for design and analysis procedures.</p></p>
<p><p><strong>References</strong></p><p>Alexiew, D., Horgan, G.J. and Brokemper, D. (2003). “Geotextile encased columns (GEC): Load capacity & geotextile selection.” BGA International Conference on Foundations; Innovations, Observations, Design and Practice, 81-90.</p><p>Idriss, I.M. and Boulanger, R.W. (2008). <em>Soil Liquefaction During Earthquakes</em>, Earthquake Engineering Research Institute Monograph MNO-12, 235 pp.</p><p>Raithel, M., Kirchner, A., Schade, C., and Leusink, E. (2005). “Foundation of constructions on very soft soils with geotextile encased columns- State of the art.” <em>Geotechnical Special Publication, Innovations in Grouting and Soil Improvement, 136</em>, 1867-1877. <a href="http://ascelibrary.org/doi/abs/10.1061/40783%28162%2920">http://ascelib…, M. and Henne, J. (2000). “Design and numerical calculation of a dam foundation withgeotextile coated sand columns.” Paper no. G11. <em>Proc. 4th International Conference on Ground Improvement Geosystems</em>, Helsinki, Finland, Building Information Ltd., <a href="http://www.rakennustieto.fi">www.rakennustieto.fi</a></p><p>Youd, T.L., Idriss, I.M., Andrus, R.D., Arango. I., Castro, G., Christian, J.T., Dobry, R., Finn, W.D.L., Harder, L.F., Hynes, M.E., Ishihara, K., Koester, J.P., Liao, S.S.C., Marcuson, W.F., Martin, G.R., Mitchell, J.K., Moriwaki, Y., Power, M.S., Robertson, P.K., Seed, R.B., and Stokoe, K.H. (2001). “Liquefaction Resistance of Soils: Summary Report from the 1996 NCEER and 1998 NCEER/NSF Workshops on Evaluation of Liquefaction Resistance of Soils”, J. of Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 127, No. 10, pp. 817 - 833. <a href="http://ascelibrary.org/doi/abs/10.1061/%28ASCE%291090-0241%282001%29127…; </strong></p></p>