Analytical model to predict building deflections induced by ground movements

International audienceThe building relative deflection is a parameter used to assess the level of the damage of the building when influenced by ground movements due to tunnelling or subsidence. The goal of this paper is to improve an analytical model that can predict the building-relevant relative deflection, induced by ground movements, by considering the soil–structure interaction phenomena. The Pasternak model is investigated to take into account the influence of the shear strain in the ground. The building is modelled with a Euler–Bernoulli beam placed on an initially deflected ground equivalent to the free-field ground movements. The static and the cinematic equilibrium of both the ground and the building are calculated to assess the transmitted building deflection. Mechanical parameters of the soil of the analytical models are discussed, and a methodology is developed to determine their values. Final results are compared with numerical finite element models (CESAR-LCPC) with a good agreement. They show the importance of the shear deformation of the soil that must be taken into account for a more confident prediction of the transmitted building deflection. To facilitate the operational use of the results, an abacus, relating the deflection ratio to the relative stiffness, is plotted