Culvert ModelingExpansion and Contraction Coefficients at the 4 cross-sections for a culvert (example) Expansion Contraction Cross-Section 4 (furthest US) 0.5 0.3 Cross-Section 3 0.5 0.3 Cross-Section 2 0.5 0.3 Cross-Section 1(furthest DS) 0.3 0.1 10 Ineffective Flow Areas 11 Adding the Culvert(s) 12 Input Requirements for Culverts. Figure (2-4). 3.1.4 The Survey Team shall ensure that all setting out works are in order. The foundation for box culverts can be designed as a conventional concrete footing with steel footer pads or a full steel invert. reinforced slab is installed on side of box culvert to minimize the distresses, length of the reinforced slab is fixed as 6m in Korea without any theoretical consideration. Either subcritical or pressure flow exists in the. This means that the fluid flow is from a high point to a low point with a consistent grade. These bridges are manufactured from a standard structural plate or deep-corrugated structural plate. The design of the road drainage system shall be "Need 0