An improved creep correction factor for the settlement of shallow foundations on sand based on macro-element simulations

In many settlement prediction methods, the creep settlement of shallow foundations on sand has been either disregarded or accounted for using time correction factors that lack a reliable basis. These existing settlement correction factors for creep have mainly been derived from a restricted number of long-term settlement measurements, and do not consider the influence of factors such as the load level, rate of load application and properties of soil below the foundation. A newly proposed one-dimensional (1D) elasto-viscoplastic macro-element is employed in this study to investigate the factors influencing the time-dependent behaviour of shallow foundations on sand. The safety factor of the foundation, the creep characteristic of the soils and the duration of load application are found to have an important effect on the post-construction settlement development. The simulation results are used to develop an enhanced settlement correction factor for creep, which takes into account the identified factors. The improved settlement correction factor is shown to be comparable to existing ones when the safety factor of the foundation is 3. The effectiveness of the proposed settlement correction factor is demonstrated using creep settlement measurements from one field footing test and two case histories.