Gross Pressure Intensity given Net Pressure Intensity Calculator

Gross Pressure Formula:

\[ q_g = q_n + \sigma_s \]

Gross Pressure (q_g): kPa

1. What is Gross Pressure Intensity?

Definition: Gross pressure is the total pressure at the base of the footing due to the weight of the superstructure and earth fill if any.

Purpose: It helps geotechnical engineers determine the total load exerted on soil for foundation design.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ q_g = q_n + \sigma_s \]

Where:

\( q_g \) — Gross pressure intensity (kPa)
\( q_n \) — Net pressure intensity (kPa)
\( \sigma_s \) — Effective surcharge (kPa)

Explanation: The net pressure is added to the effective surcharge to obtain the total gross pressure.

3. Importance of Gross Pressure Calculation

Details: Proper calculation ensures foundation stability, prevents soil bearing capacity failure, and helps in accurate structural design.

4. Using the Calculator

Tips: Enter the net pressure and effective surcharge in kPa, and optionally specify a tolerance percentage (default ±5%).

5. Frequently Asked Questions (FAQ)

Q1: What is net pressure intensity?
A: Net pressure is the difference between the total pressure exerted on a soil mass and the pore water pressure within the soil.

Q2: What is effective surcharge?
A: Effective surcharge refers to the vertical pressure or any load that acts over the ground surface additional to basic earth pressure.

Q3: Why include a tolerance percentage?
A: The tolerance accounts for measurement uncertainties and variations in material properties (±5% is typical).

Q4: How do I determine net pressure?
A: Net pressure is typically calculated as the structural load divided by foundation area minus the original overburden pressure.

Q5: What units should I use?
A: This calculator uses kilopascals (kPa) for all pressure values. 1 kPa = 1 kN/m².