## 1 Introduction  
[PERSON] et al.'s [1] strain influence factor method (or stress-strain method) for immediate settlement analysis is among the most popular ones worldwide. In brief, the method in question incorporates the use of a bilinear strain influence factor \(I_{z}\) versus \(z\)/\(B\) relationship (\(z\) is the depth measured from the foundation level and \(B\) is the width of foundation); the area under this relationship multiplied by the net footing loading and divided by the elastic modulus of soil, \(E\), gives the footing settlement. As \(I_{z}\) is depth-specific and so is the elastic modulus of soil, the method in question can take into account the fluctuation of \(E\) with depth. [PERSON]'s method has been modified by various researchers [2; 3; 4; 5; 6; 7], who, however, kept the crude bilinear approximation. This semi-empirical approach is suggested by or included in various countries' design codes and public agencies' reference manuals, such as AASHTO, EN 1997-2 and Samtani and Nowatzki [8; 9; 10]. However, in the forthcoming revision of Eurocode 7 (prEN1997-3:202x), [PERSON]'s stress-strain method has been abandoned; it recommends instead the stress-strain method deriving from pure elasticity. An in-depth review of [PERSON]'s method has recently been offered by the author [11]. Indicatively, it is mentioned that independent studies [2; 12; 13; 14; 15; 16; 17; 18; 19] comparing the measured settlement of structures or full-size test footings with the respective settlement calculated with [PERSON]'s method indicate great deviation. This deviation can be attributed to the replacement of the actual curved \(I_{z}\)-\(\beta\) relationship with a simplistic bilinear one, the way the embedment depth is taken into account, the plastic response of the ground and the fact that [PERSON]'s method was developed considering [PERSON]'s ratio values in the order of 0.4 to 0.5. For the latter, [PERSON] and [PERSON] [20] pointed out that accurate measurements using local strain devices mounted midlevel on soil specimens and measured internally to the triaxial cell have shown that the appropriate value of Poisson's ratio for use in elastic continuum solutions for drained loading is \(0.1<\
u<0.2\) for all soil types [20; 21; 22].  
Strain influence factor values derived from the theory of elasticity can be found in various sources [23; 24]; however, these are example curves referring to a very limited number of cases. In the present paper, the problem in question is studied on a systematic basis, giving strain influence factors for the most common cases met in practice--i.e., for uniformly loaded flexible and rigid circular footings, uniformly loaded flexible rectangular footings and triangular and trapezoidal embankment loading. The settlement under the so-called \"characteristic point\" of flexible footings is also investigated; the settlement under this point is considered to be the same as the uniform settlement of the respective rigid footing. The calculation of settlement based on strain influence factors (strain-strain method) offers the advantage of considering non-uniform elastic moduli profiles with depth (e.g., linearly varying modulus with depth or different elastic moduli due to soil stratification), such as those often obtained in practice using continues probing tests--e.g., the Cone Penetration Test (CPT) and Standard Penetration Test (SPT).