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How a simple beam deflection is checked
The elastic formulas for a simply supported beam, and the check they are not.
The beam page checks the elastic deflection of a simply supported beam. E and I are the values you enter. It is not a code check, and it is not a design.
The two loads
- A point load at midspan deflects PL³/48EI and the moment is PL/4.
- A uniform load deflects 5wL⁴/384EI and the moment is wL²/8.
Enter the second moment I in cm⁴ and the modulus E in GPa. A 10 kN point load on a 4 m span, with E of 200 GPa and I of 2000 cm⁴, deflects 3.33 mm and the moment is 10 kN·m. Confirm the section and the load against the drawings before you use the number.