Percent Composite

Stresses

Stresses are computed by interpolating the section modulus between fully composite and non composite. Using the section modulus for each face of the partially composite system, an effective section modulus is computed based on the location the stress is being computed at.

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Figure 1: Section Modulus Interpolation

Deflections

When computing deflections, the partially composite section properties are used. These are interpolated using the deflection percent compute the user input. If the member is cracked, cracked section properties are computed using the full section. Because these properties are not interpolated, they are only used if the section properties decrease.

Ultimate

For ultimate strength, the capacity is calculated using the fully composite and non composite section. These results are interpolated between using the percent composite value provided. For shear, fully composite is always assumed.