What is group action of piles?
clay. a. Group action. Piles driven in clay derive their capacity from friction. They are commonly driven in groups or clusters beneath individual footings or as single large groups beneath mats or rafts.
What are the benefits of using piles in a group?
Pile group has large foundation bearing capacity, small settlement, and good stability. It can also reduce the flow resistance and local scour, and there are also many other advantages, therefore it is widely used as the water structure foundation for cross-river and sea bridge, port and wharf and marine platform.
What is group capacity of pile?
Capacity of pile group is the sum of the individual capacities of piles, but it is influenced by the spacing between the piles. Piles are driven generally in groups in regular pattern to support the structural loads. The structural load is applied to the pile cap that distributes the load to individual piles.
What is Feld’s rule?
The use of Feld’s rule is probably the simplest. It states that the load capacity of each pile in a group is reduced by 1/16 on account of the nearest pile in each diagonal or straight row.
What is group efficiency?
Instead of focusing on a single ligand, group efficiency compares two ligands that differ by the presence or absence of a given group of atoms. To calculate GE, you simply subtract the ΔG values for the two ligands and divide by the number of heavy atoms in the group.
What are the factors affecting on pile group efficiency?
The four influential factors are the inclination angle of side piles Φ, the length of the side piles L, the diameter of the side piles D, and the number of piles n.
What is pile group efficiency?
Thus, the pile group efficiency is equal to the ratio of the average load per pile in the group at which the failure occurs to the ultimate load of a comparable single pile.
What is difference between single pile and group pile?
The failure mechanism of a group of pile is very much different from that of a single pile. In a pile group the piles and soil enclosed by the group act as a single unit. Block failure may occur in a pile group as in the ease of spread foundation and slip plane occurs at the perimeter of the pile as shown in Fig.
What is group efficiency factor?
Group efficiency factor is the ratio of uplift resistance of group of piles to the uplift resistance of single pile. It is to be noted here that the weight of single pile and weight of soil enclosed by pile group are neglected in the respective cases of uplift resistance of single pile and pile group.
What is block failure of pile group?
Block failure occurs generally when the spacing of piles is less than about three times the pile diameter. In this case, the soil, bound by a perimeter of the pile group over the embedded length, acts as a single unit or block. Individual pile failure occurs when the piles are spaced at about eight times the diameter.
What is the meaning of pile group?
A pile group is a set of piles that have a pile cap that means that they act together to carry the load. The pile cap would normally be in contact with the ground. The piles would be designed to share the pile load at ultimate state.
How is the load transmitted to the pile group?
The load is generally transmitted to the pile group through an R.C.C slab. The load acts on the pile cap which distributes the load to the piles. The bearing capacity of a pile group may or may not be equal to the sum of the bearing of individual piles constituting a group.
What is a group of piles?
The group of piles acts as a pier foundation having a base equal to the gross plan area contained between the piles. For driven piles bearing on dense, compact sand with a spacing equal to or greater than three times the diameter of the pile, the group capacity generally takes as the sum of individual capacity. Thus,
How is the settlement of pile groups in granular soil calculated?
The settlement of pile groups in granular soils can be calculated in a manner similar to that employed for pile groups in clay. In this case a virtual raft is assumed at the base of the pile. The settlement is calculated using the results of Dutch cone or Standard penetration tests.
How piles are used in construction?
For walls, piles are used in a staggered pattern on both sides of its centerline. The load is generally transmitted to the pile group through an R.C.C slab. The load acts on the pile cap which distributes the load to the piles.