Distribution Reinforcement

LRFD

When the fill depth is less than 2 feet, see Article 9.7.3.2, in which the distribution steel must be equal to or greater than the following percentage of the flexural steel:

For primary reinforcement parallel to traffic:

For primary reinforcement perpendicular to traffic:

When the fill depth is greater than 2 feet, Article 5.15.4.1 states that distribution steel is not required. Therefore, Eriksson Culvert uses shrinkage and temperature steel as a minimum check.

Standard Specification

According to Section 6.5, when the depth of the fill exceeds 2 feet, reinforcement to provide for the lateral distribution of wheel loads in not required. Top slabs with less than 2 feet of fill must have distribution steel that satisfies the following percentage of the flexural steel:

For both specs, when the fill depth is less than 2 feet, the program uses epoxy coated bars in the top face of the top slab when requested by the user. Note that this is a requirement in most states.

CHBDC

Per 7.8.12.1 (a), top slabs of box sections having a depth of cover of less than 0.6m shall be provided with distribution reinforcement in accordance with 8.18.7, to be placed near the inside of the bottom face of the slab.

Per 8.18.7, distribution reinforcement shall be placed transverse to the main reinforcement. The amount of distribution reinforcement as a percentage of the main reinforcement shall be:

For main reinforcement parallel to traffic:

%Steel = 55 / √S, maximum 50%, where S = effective span length in meters

For main reinforcement perpendicular to traffic:

%Steel = 120 / √S, Maximum 67%, where S = effective span length in meters