A fully compensated raft foundation for a building is

Explanation:

A fully compensated raft foundation (also called buoyant raft) is designed so that the weight of the soil excavated for the foundation equals the weight of the building and the foundation combined.

• This compensation reduces the net increase in stress on the soil, minimizing settlement.

• It is especially useful in soft or compressible soils where minimizing settlement is critical.

• The idea is that the removal of soil weight balances the load, so the foundation does not cause additional stress on the soil below.

Additional InformationRaft Foundation (or mat foundation) is a large, continuous slab supporting multiple columns and walls, spreading the load over a wide area. It is used when soil bearing capacity is low or loads are heavy.

Types of Raft Foundations

• Rigid Raft: Assumes the raft acts as a stiff plate, distributing loads uniformly.

• Flexible Raft: Assumes the raft bends and deflects under loads, distributing unevenly.

• Fully Compensated Raft: Designed so that the weight of the soil excavated equals the weight of the building and foundation.

Fully Compensated Raft Foundation

• Also known as buoyant foundation or compensated foundation.

• The purpose is to neutralize the additional load on the soil by removing an equivalent weight of soil during excavation.

• Reduces settlement by minimizing changes in stress on the underlying soil.

• Commonly used in soft, compressible soils or areas with high water tables.

• Helps prevent excessive consolidation and uneven settlement.