Improving the Uplift Capacity Performance of the Structural Skirt Foundation by Enhancing its Properties

Geotechnical engineers are making extensive efforts to improve soil properties and make it suitable and safe for the structures built above it. This research has investigated the use of skirts under shallow footing located on loose sand exposed to uplift loading as a promising method for improving the uplift capacity of soil and a suitable economic alternative to pile foundations.

A loading device, a square footing model, and two groups of skirts (chamfered and straight corners) with different properties (length, inclination angle, roughness, and wings) of the skirt were used. The performance of un-skirted footing situated on loose sand with 30% relative density was analyzed and compared with skirted footing.

The results showed that adding (Hy-Rib) metal lath and wings to the skirt significantly improved the uplift capacity. For the footing at L/B = 2 (where L is the skirt length and B is the footing width) and a skirt inclination angle of 0°, the maximum values were 7 and 12 times higher than for the un-skirted footing. When the inclination angle was increased to 45° while maintaining the same embedment ratio of L/B = 2, the uplift capacity significantly increased, reaching values of 27 and 20 times for the straight and chamfered corners with the (Hy-Rib) addition, respectively, and 38 and 27 times for the straight and chamfered corners with the wings added.

A significant increase in the uplift capacity of soil was observed by improving its properties by adding a skirt to the shallow footing and making modifications to it using expanded metal lath (Hy-Rib) and wings. The use of skirts has proven to be economically feasible and a successful and promising alternative to the use of uplift piles.