Calculation of Settlement of Spread Foundation (EC7 Part 2)

April 18, 2018

In this post, we are going to talk about an approach described in Annex E of EN 1997-2:2006 (Eurocode 7 Part 2) for determining the settlement of spread foundations. This is based on semi-empirical method and the result of MPM test (Menard Pressuremeter Test).

The formular for evaluating the settlement of a spread footing is given below;

where;
B_o is a reference width of 0.6 m;
B is the width of the foundation;
λ_d , λ_c are shape factors given in Table E.2;
α is a rheological factor given in Table E.3;
E_c is the weighted value of E_M immediately below the foundation;
E_d is the harmonic mean of E_M in all layers up to 8 × B below the foundation;
σ_v0 is the total (initial) vertical stress at the level of the foundation base;
q is the design normal pressure applied on the foundation.

The Table E.2 and E.3 of EC7-2 are given below;

Solved Example
2m x 2m square footing is carrying a quasi-permanent SLS combination load of 1040 kN. The Menard Pressuremeter moduli values are as given in the sketch below. Calculate the settlement of the foundation if the unit weight of the first layer of soil is 18.5 kN/m³.