Transverse stiffness is provided by bottom anchoring. Cluster and skirt piles, or other foundation system, anchor the structure and transfer both vertical and horizontal actions to the seabed.
It should be designed to with stand all actions, operational and accidental loads, with enough strength and stiffness. SFT is subjected to all environmental actions typical in the water environment: wave ,current, vibration of water level, earthquake, corrosion, ice and marine growth. This method is limited to 100 meters water depth Negative buoyancy: Here the foundations would be piers or columns to the sea or lake. Floating foundation is also called balancing raft and. Here SFT is mainly 30 metres below the water surface. A floating foundation is a type of foundation constructed by excavating the soil in such a way that the weight of structure built on the soil is nearly equal to the total weight of the soil excavated from the ground including the weight water in the soil before the construction of structure. Positive buoyancy : In this the SFT is fixed in position by anchoring either by means of tension legs to the bottom or by means of pontoons on the surface. There are two ways in which SFT can be floated. Minimum internal dimension often result in a near optimum design. Rebar and welded wire reinforcing are used. A single reinforced concrete slab supports the building. Title: 3 pilescaissonsrafts 05 copy. Light buildings built on soft soil use floating foundations. When the weight of building is equal to the weight of the soil removed (displaced) by the raft, no extra weight is placed on the soil. The relation between buoyancy and self weight is very important, since it controls the static behaviour f the tunnel and to some extend, also the response to dynamic forces. The monolithic footing and foundation shown here acts as a floating raft for the building above. SFT is a buoyant structure which moves in water. The Submerged floating tunnel utilizes lakes and waterways to carry traffic under water and on to the other side, where it can be conveniently linked to the rural network or to the underground infrastructure of modern cities. It supported on columns or held in place by tethers attached to the sea floor or by pontoons floating on the surface. The Submerged floating Tunnel is a tube like structure made of Steel and Concrete utilizing the law of buoyancy. The submerged floating tunnel is an innovative concept for crossing waterways, utilizing the law of buoyancy to support the structure at a moderate and convenient depth. As the needs of society for regional growth and the protection of the environment have assumed increased importance, in this wider context the submerged floating tunnel offers new opportunities. The Submerged Floating Tunnel concept was first conceived at the beginning of the century, but no actual project was undertaken until recently.