HOW TO CALCULATE PILE LOAD CAPACITY USING STATIC CONE PENETRATION TEST?

Pile Load Capacity Calculation Using Static Cone Penetration (SCPT) Test Data

The safe load capacity of bore cast in situ piles can be calculated using test data obtained from Static Cone Penetration Test as described below.

We know that the final load capacity of a pile consists of two terms, namely

• end bearing resistance
• skin abrasion resistance

So we need to calculate the above two parameters, then by adding these two parameters we can get the final load capacity of the pile.

Step-1 (Calculate the end-bearing resistance of the pile)

The final end bearing resistance of the pile is calculated using the formula below.

Where,

Why_You = final end bearing resistance, kN/m . In²

Why_c0 = kN/m . Average static cone resistance at a depth of 2d below the pile tip in²

Why_C1 = kN/m . Minimum static cone resistance at the same 2D below the pile tip in²

Why_c2 = in kN/m, the average of the envelope of minimum constant cone resistance values ​​over a pile length of 8D above the pile tip²

d = diameter of the pile

Step-2 (Calculate Skin-Abrasion Resistance)

For a variety of soils, the ultimate skin abrasion resistance (f.)_s), kN/m. In², can be obtained using the table below.

where, why_C kN/m . has cone resistance²,

Step-3 (Calculate Safe Heap Load Capacity)

Add end end bearing resistance (Q_You) and ultimate skin abrasion resistance (f.)_s) as calculated in step-1 and 2 respectively, and divide it by the appropriate factor of safety (minimum 2.5) to obtain the safe load capacity of the pile, i.e.

Why_Safe = (Q_You+f_s) / FOS

Where,

Why_Safe = safe load capacity of the pile

Why_You = End end bearing resistance of pile

F_s = final skin abrasion resistance of the pile

FOS = heap protection factor (usually 2.5)

Reference

IS: 2911-Part-1-Sec-2