Eriksson Culvert follows ACI 350 chapter 9 for strength and serviceability requirements. This states that the required strength for non-compression controlled sections shall be multiplied by the environmental durability factor.
Calculation of Environmental Durability Factor
where f_s is 20,000 psi for normal exposure and 17,000 psi for severe exposure.
The strain gradient amplification factor (beta) in these equations is calculated as:
It is permitted to use beta of 1.2 if h >= 16” and 1.35 if h < 16”.
It is also permitted to use 25 for the 4(2 + d_b/2)^2 term as a simplification.
Applying the Environmental Durability Factor in Eriksson Culvert
To have Eriksson Culvert apply these durability factors in the design, simply select “Apply environmental durability factors” on the Analysis Options window. You will also be required to select the exposure level.
Eriksson Culvert will then automatically calculate the required durability factors and multiply the design moments by them, creating a more conservative design. The calculated factors will be displayed in the text report for your reference:
