This paper used finite element modeling to evaluate the consolidation effect on the performance of existing rafts underpinned with micropiles under combined vertical and lateral loads. For this purpose, a real-life case study was discussed, in which micropile underpinning was used to stop the continuous tilt of a 13-floor residential building supported by a surface raft. It was found that the building tilted towards the northeast direction because of the consolidation of a deep soft clay layer under the northeast building corner. After discussing the as-built micropiling system, a 3D numerical model, developed using the PLAXIS software, was used to conduct the numerical research. The time-dependent behavior of the raft with and without the consideration of micropiles was assessed. Moreover, the variation of load-sharing ratios with time was investigated. The numerical results emphasize that the underpinning process was effective and reduced the final raft rotation and maximum settlement by 79.9% and 73.9%, respectively, compared to the case of the absence of micropiles. The consolidation process under a steady level of vertical loads enhanced the performance of the micropiled and unmicropiled rafts against upcoming lateral loads. The vertical load-sharing ratio increased during a life span of 20 years by 10.4% due to the consolidation process, but the increase was at a decreasing rate. Comparing all the four directions in which the lateral load was applied, the micropiles carried (57.4–76.6%) of the lateral load.