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Input values for the yield strength (fy), allowable stress, and modulus of elasticity (Es) of the reinforcing steel. The reinforcing diameter is used by the program to compute the depth to the reinforcement during the design phase. For the calculations of the critical section values, Eriksson Culvert uses the actual diameter of either the calculated or assigned flexural reinforcement. However, in Design Mode, at the time the program settles on a specific member thickness, the size of the reinforcing is not known, therefore the ‘reinforcing diameter’ is used to approximate the thickness of one layer of reinforcement. If you are using mesh, then the default value of 1 inch may be too large. You can also define the yield strength of the shear steel here as well. Note that if you switch from rebar to mesh, the program will automatically change the steel yield as well, defaulting to 60 ksi for rebar and either 65 or 70 ksi for mesh. However, the yield strength of the shear steel will not be changed. Previous versions of ACI 318 ensured the steel would fail in tension before the concrete failed in compression (i.e., ductile failure) by limiting the maximum reinforcement to 75% of the balanced reinforcement. Therefore, the default Maximum Steel Ratio Coefficient is 0.75 in Eriksson Culvert auto design mode.
Soil
Input a value for the density and Poisson’s ratio of the soil.
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