Eriksson Culvert follows the seismic analysis procedure outlined in FHWA-NHI-10-034 chapter 13. Below is an example calculation of this analysis, as well as the corresponding Eriksson Culvert file.
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Geometric Parameter | Value |
|---|---|
Clear span | 20 17.667 ft |
Clear Height | 11.66 667 ft |
Slab thicknesses | 14 in |
Wall thicknesses | 14 in |
Joint Location | 36 in up from center line |
Fill depth | 16 ft |
Haunch dimensions | 15 in depth and width |
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The internal forces can be determined through analyzing a 2D frame model with a displacement of 0.273”; though due to the formulation of FEM, it is easier to apply this as an equivalent point load of 139.5 09 kips.
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Eriksson Culvert calculates and stores these internal forces (axial, shear, and moments) at tenth points along all members in the structure for later use in the load combination equations.
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The dead load of the top slab = 1.17' * 0.16 = 0.1888 187 klf
Summing these forces gives a total dead load of 2.27 klf
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From WSDOT BDM section 8.3.4B, the ground motion attenuation ration of 1.0 .9 is applied since the depth of fill is within the range of 20' to 50less than 20'.
Now the vertical force is calculated as,
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