Comparison of shallow foundation design using Eurocode 7 and Polish Standard

Abstract

Abstract Bearing capacity of cohesive soils was calculated based on PN-B-03020:1981P and Eurocode 7. Strength parameters of cohesive soil modified by the authors: shear strength in undrained conditions cu, effective cohesion c' and effective friction angle φ' were adopted for calculations acc. to Eurocode 7. Values of these parameters depend on a leading parameter - liquidity index IL. Bearing capacity was calculated for two pad foundations of a size B × L = 2.0 × 3.0 m and 1.5 × 2.0 m and for one 2.0 × 14.0 m strip foundation. The capacity calculated acc. to EC 7 was reduced by multiplying by a factor α = 0.87 to account for different bearing capacity coefficients in Polish Norms and Eurocodes. Performed calculations showed comparable bearing capacity of substratum irrespective of adopted norms EC 7 and PN for foundation pads. In all analysed cases, however, the bearing capacity of foundation strips calculated acc. to Eurocode 7 was higher than those calculated acc. to PN-B-03020:1981P. The reason is in the values and ways of accounting partial security coefficients and in differences in the values of shape coefficients used in the equation for ultimate bearing resistance of soil substratum.