What is the minimum distance between piles?
The end bearing piles that are used in compressible soils must be spaced at a minimum of 2.5d and a spacing of 3.5d(Maximum)for those piles placed on less compressible or stiff clay soil. The Indian Road Congress specifies a minimum spacing of 3d or a distance equal to pile perimeter for the friction piles.
How do you determine the depth of a pile cap?
Consider the design of a pile cap supporting two pile and a single column on the pile cap. consider 150mm offset from the pile and space between piles as 2.5 times pile diameter. Effective depth, d = 1000-50-20/2 = 940 mm > 750mm; (2.5×600/2) Ok.
What is cut off level of pile cap?
Pile Cut-off level is the actual level at which the piles below pier are made to be of the same level. The concrete of pile is cut-off at the specified level (given in the specifications or drawings usually around 75 mm) while the steel is kept projected in-to the pile cap to make an effective bond.
How is pile cap reinforcement calculated?
Total Cutting Length for Vertical Reinforcement = Anchorage Length at the bottom of the pile + the height of the pile + development length (40d) + Lap length (50d) – clear cover provided at the bottom.
How do you calculate the number of piles?
Both the dynamic and static formulas indicate that an allowable load of 15 tons per pile is reason- able. The number of piles required to support the load is 180/15 = 12 piles.
What is the length of pile in friction pile?
Square concrete piles from 60 to 90 cm are commonly used with larger sizes up to 3 m that are less common, but used for major bridges. These are typically used as friction piles but can be outfitted with steel driving tips for driving to rock or very dense soil to develop high end-bearing.
Is a pile cap a footing?
It usually forms part of the deep foundation of a building, typically a multi-story building, structure or support base for heavy equipment, or of a bridge. A similar structure to a pile cap is a “raft”, which is a concrete foundation floor resting directly onto soft soil which may be liable to subsidence.
How do you calculate moment in pile cap?
The calculation of the moment at the face of column is as follows: Thus, the program uses the factored pile forces multiplied by their horizontal distance to the face of column and subtracts the self-weight of the pile cap and overburden in this area multiplied by its moment arm.
Is code for pile boring?
Following are the Indian Standard Codes on Pile Foundations: IS 2911 : Part 1 : Sec 1 : 1979 Driven cast in-situ concrete piles. IS 2911 : Part 1 : Sec 2 : 1979 Bored cast-in-situ piles. IS 5121 : 1969 Safety code for piling and other deep foundations.
How do pile caps work?
Pile caps are constructed by excavating an area around the group of piles to enable formwork to be inserted. A reinforcement cage is then built and positioned in the formwork cast box and fastened to the piles. The concrete is then poured and left to cure, after which the formwork is removed..
What is effective length of pile?
Calculation of effective pile length. The value of shaft resistance is assumed equal to 0 at the top of pile and the effective pile length firstly increases and then decreases along the pile. There is no displacement at the point of effective pile length.
What’s the minimum edge distance for a cap?
If you have a pile connected to the cap with dowels, you want enough distance for the longitudinal cap edge bars to pass outside the pile dowels. Also, consider pile location tolerances in addition to the bar clearance distance. We typically design 18″ to 24″ prestressed concrete piles or 24″ to 48″ steel piles.
What’s the minimum edge distance for a pile?
The minimum pile spacing is the largest of 2-ft + dp, 3-ft, and 3 * dp, where dp is the pile diameter, otherwise the capacity of the piles would be affected by adverse group effects. The minimum edge distance varies from 15″ for 60-Ton piles to 36″ for >280-Ton piles.
What should the spacing be on a pile cap?
The column or wall on pile cap should be centered at the geometric center of the pile cap in order to transferred load evenly to each pile. Example of pile layout pattern are shown below: In general, piles should be spacing at 3 times of pile diameter in order to transfer load effectively to soil.
What are the rules of thumb for pile design?
Most of the pile cap are designed by short-cut or thumb rule procedures for spacing of piles, thickness of pile cap and minimum edge distance of pile cap from pile center or edge. In the present paper, finite element analysis of pile cap is performed to capture the behavior of pile cap under axial load and moment.