Analysis of beams on reinforced granular beds

This paper presents a model for estimating the flexural response of beams resting on reinforced beds with reinforcing elements, such as geogrids, which are idealised as beams with smooth surface characteristics. The lower poor strata and the upper dense soil are modelled using Winkler springs of different stiffnesses. Taking a surcharge load on the reinforcing elements has incorporated the effect of depth of placement of the reinforced layer. The governing differential equations to find the response of the model have been derived, and closed-form analytical solutions are found subjected to appropriate boundary and continuity conditions. A particular case of the present study matches identically when compared with the solution obtained by Hetenyi for an infinite beam on an elastic foundation. For the range of parameters considered, the results show that practically no change occurs in the normalised deflection of upper and lower beams when the normalised length ratio of beams exceeds 1.5. Further, it is shown that the various parameters—the ratio of flexural rigidity of upper and lower beam, the ratio of stiffness of the upper and lower soil layers, and the ratio of the length of upper and lower beams and placement depth of the lower reinforcement—significantly affect the combined response of the model.