Ultimate Bearing Capacity of Strip Footing on Granular Soil Under Eccentrically Inclined Load- A Numerical Approach

Abstract

Since the publication of Terzaghi’s theory on the ultimate bearing capacity of shallow foundations in 1943, results of numerous studies—theoretical, experimental and numerical—by various investigators have been published. Most of the studies relate to the case of a vertical load applied centrally to the foundation. Meyerhof (1953) developed empirical procedures for estimating the ultimate bearing capacity of foundations subjected to eccentric and inclined loads. Recently, Patra et al. (2012a, 2012b) developed two empirical equations to determine the ultimate bearing capacity of eccentrically inclined loaded strip footing. Based on the review of the existing literature on the bearing capacity of shallow foundations, it appears that limited attention has been paid to estimate the ultimate bearing capacity when the foundation is subjected to both eccentric and inclined load and the objective of present study stems from this paucity. In order to arrive at the objective and to quantify certain parameters, extensive numerical models have been made to determine the ultimate bearing capacity of shallow strip foundation resting over sand bed and subjected to eccentric and inclined loads. The models are made with three relative density of sand i.e. dense sand and medium dense sand. The load inclination has been varied from 0° to 20° whereas the eccentricity varies from 0 to 0.15B (B = width of footing). Depth of the footing is varied from 0 to B with an increment of 0.5B. In most cases of analysis of such problems; the line of load application is towards the center line of the footing. However, in this thesis, it is investigated for the two possible ways of line of load application i.e. (i) towards and (ii) away from the center line of the footing. Based on the analysis of numerical models result, the results of medium dense and dense sand are compared with the reduction factor developed by Patra et al. (2012a, 2012b) for each mode iv of load application. This reduction factor will compute the ultimate bearing capacity of footing subjected to eccentric and inclined load by knowing the ultimate bearing capacity of footings under centric vertical load at the same depth of footing. Finally, the numerical model results are compared with the existing theories and the comparison seems to be good