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At the left end or right end of a member where sections are located less than a distance d from the face of the support, they will be designed for the same shear, V, as that computed at a distance d. For LRFD, substitute dv for d. Note that in LRFD C5.13.3.6.1/C5.12.8.6 (2nd Paragraph), the design section may be taken at a distance dv past the end of the haunch.
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For fill height greater than or equal to 2 feet (and AREMA):
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Per LRFD 5.14.5.3/5.12.7.3, the provisions of 5.8/5.7 apply to fill depths less than 2 feet for both the sidewalls and the slabs. Eriksson Culvert calculates the shear resistance of the concrete using the simplified approach as allowed in LRFD 5.8.3.3/5.7.3.3, and assumes a beta value of 2.0 (except when the member thickness is greater than or equal to 16 inches, see below). This leads to the calculation of Vc and Vc,max as follows (Vp is equal to zero as this is a non-prestressed member):
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Where the member thickness is equal to or greater than 16 inches or the member is in tension, the program uses the iterative approach in Appendix B5 for the calculation of beta used in Eq. 5.8.3.3-3/5.7.3.3-3, due to the lack of transverse reinforcing assumed in the design algorithm. A value is assumed for theta, which is used in Eq. B5.2-1. From this we can use Table B5.2-1 to look up a new value for theta. This process is repeated until successive values for theta are approximately the same. Once the calculations for theta have converged, theta is used in Table B5.2-1 to obtain a value for beta.
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For fill depths greater than 2 feet, the horizontal slabs the provisions of Article 5.14.5.3/5.12.7.3 shall apply. Note that this section uses de instead of dv.
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