The model tests studied how piles and rafts interact under extreme loads. Group piles with 4 times the diameter spacing acted like a solid foundation. Piles with larger spacing reached their limit before the soil under the raft did. The load distribution between piles and rafts changed during the tests. Piles with 6 times the diameter spacing had a consistent load distribution. The spacing between piles affected how much the soil moved sideways. Rafts in group piles behaved like regular raft foundations. The soil stress under the pile tip was influenced by the load carried by the rafts. A spacing of 6 times the diameter separated normal piled raft foundations from composite pile foundations.