How to Calculate a Concrete Pad Load

Concrete pads must be able to withstand hundreds of pounds of force from the supporting structures placed on them. Frequently, steel beams rest on concrete pads in the basement of large buildings to support the weight of the structure. The load is the amount of force in pounds supported by the concrete pad. The weight of the load is related to the amount of stress that the concrete pad can withstand, assuming it does not break, as well as the pad's area.

Things You'll Need

• Tape measure
• Calculator

Instructions

1. Measure the length and width of the top surface of the concrete pad in inches. For example, assume the length is 20 inches and the width is 15 inches.

2. Multiply the length by the width to obtain the pad area in square inches. Continuing the exercise, 20 inches times 15 inches equals an area of 300 square inches.

3. Multiply the area by the stress rating for the concrete to obtain the maximum load the concrete pad can support in pounds. Typical concrete can withstand a stress of 2,900 lbs. per square inch before failing. Using this figure as an example, 300 square inches times 2,900 lbs. per square inch equals a load of 870,000 lbs.

Tips & Warnings

• Consult the manufacturer for the stress capacity of your specific concrete before use.

References

• "Physics for Scientists and Engineers with Modern Physics"; Raymond A. Serway and John W. Jewett; 2009
• Georgia State University: HyperPhysics: Young's Modulus
• Wolfram MathWorld: Area