The study looked at how adding a cap to a single pile affects its ability to resist sideways forces in clayey soil. They used computer simulations to test different pile sizes and lengths, as well as pile groups. The results showed that the size of the cap can change how well a single pile can resist sideways forces. In pile groups, the interaction between piles and the cap can also affect the resistance of the leading pile. The study found that adding a cap can increase the resistance of the leading pile in a group.