Using the elastic continuum approach for the analysis ofbeam on elastic foundation, a method is developed to calculate an equivalent coefficient of subgrade reaction k to use in the Winkler model. It is shown that dividing the contact pressure produced from elastic continuum model by the corresponding settlement along the beam length generates length dependent coefficient of subgrade reaction that accurately describes the interaction between the beam and the supporting soils. Results from the developed I equivalent k parameter are compared with those from elastic continuum model and by using different k values predicted by other methods that are currently in use. For uniformly loaded beam, graphs and regression equations are provided from which an equivalent k value at different positions along the beam length (eg, at the center and the edge of the beam) can be calculated as a function of the elastic soil properties and the rigidity of the beam