Design Charts for Foundation System Reinforced with Peripheral Vertical Inserts

It is a well established fact that the response of a soil mass can be considerably improved by inserting vertical reinforcement around the periphery of the footing. The improved soil mass behaves as a coherent mass and shows promising results. This can be advantageous to satisfy the strength as well as settlement criterion of a foundation system. Moreover, the desired results could be accomplished without disturbing the existing footings of a structural system. In the present paper, the results are derived through parametric study. These are presented in the form of design charts that can be employed to decide the geometric parameters of vertical inserts to obtain the desired response of the foundation system in terms of bearing capacity and settlement. Finite element software viz: PLAXIS is used to develop a parametric numerical model of the foundation system. It is used to determine the percentage reduction in absolute or differential settlement and relative improvement of bearing capacity achieved by inserting vertical inserts around a rectangular footing. In the present study, it is found that the load bearing capacity of existing footings may be increased by inserting vertical inserts up to 137%. For improving maximum load bearing capacity, edge distance of vertical inserts should be as minimal as possible. The overall and differential settlement of footing may be reduced to 40% and 5%, respectively. It is also observed that optimum C/C spacing of vertical inserts is 2.66-3.33 times the diameter of vertical inserts.