Factored Axial Load on Member given Gross Area of Concrete Calculator

Factored Load Formula:

\[ P_{fm} = (0.4 \times f_{ck} + \frac{p}{100} \times (0.67 \times f_{y} - 0.4 \times f_{ck})) \times A_{g} \]

Characteristic Compressive Strength:

Percentage of Compression Reinforcement:

Characteristic Strength of Steel Reinforcement:

Gross Area of Concrete:

m²

Factored Load on Member (N):

1. What is Factored Axial Load on Member?

Definition: This calculator determines the factored axial load capacity of a reinforced concrete member based on its gross area and material properties.

Purpose: It helps structural engineers and designers verify the load-carrying capacity of concrete members under axial compression.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ P_{fm} = (0.4 \times f_{ck} + \frac{p}{100} \times (0.67 \times f_{y} - 0.4 \times f_{ck})) \times A_{g} \]

Where:

\( P_{fm} \) — Factored load on member (N)
\( f_{ck} \) — Characteristic compressive strength of concrete (Pa)
\( p \) — Percentage of compression reinforcement (%)
\( f_{y} \) — Characteristic strength of steel reinforcement (Pa)
\( A_{g} \) — Gross area of concrete (m²)

Explanation: The formula combines the concrete's compressive strength with the contribution of steel reinforcement to determine the member's capacity.

3. Importance of Factored Load Calculation

Details: Proper calculation ensures structural safety by accounting for material strengths and reinforcement while applying appropriate safety factors.

4. Using the Calculator

Tips: Enter all material properties in Pascals (Pa), reinforcement percentage (%), and concrete area in square meters (m²). All values must be > 0 except percentage which can be 0.

5. Frequently Asked Questions (FAQ)

Q1: What is characteristic compressive strength?
A: It's the concrete strength below which not more than 5% of test results fall, typically specified at 28 days.

Q2: How is percentage of compression reinforcement calculated?
A: It's the ratio of steel area to concrete area, expressed as a percentage (typically 1-4%).

Q3: What's a typical value for fy?
A: Common values are 415 MPa (415,000,000 Pa) for Fe 415 steel or 500 MPa for Fe 500 steel.

Q4: Does this include safety factors?
A: Yes, the formula includes built-in safety factors through the 0.4 and 0.67 coefficients.

Q5: When would I use zero reinforcement percentage?
A: For plain concrete members without any steel reinforcement.