Design & Specification
Bison Precast can accommodate a variety of specialist manufactured components to satisfy scheme design requirements.
Cast on end walls
Animal crossing ledge
Twin cell construction
Design & detailing
Bison Precast Box Culverts are designed in accordance with BS EN 14844, Eurocodes, PD6694, BS EN 13369, BS EN 206, BS 8500 and BRE Special Digest 1.
Exposure & cover requirements
Depending on the depth of fill, proximity to a highway and the environmental conditions the units will be designed in accordance with Table 1. Minimum concrete grade used is C45/55 with a maximum aggregate size of 20mm. Please refer to BS8500 Table A.1 for further details.
Breaking & acceleration
In accordance with Eurocodes the breaking and acceleration force generated from traffic loading needs to be considered.
Surface loading & fill depth
Loading applied at the ground surface and weight of fill material produce a combination of vertical and horizontal forces on the box culvert.
Surface loading may be specified as a standard loading type, equivalent uniform loading or individual wheel loads. The critical load on a culvert can occur at minimum or maximum fill.
Each enquiry for a culvert should state the minimum and maximum fill depth and the amount or type of surface loading.
It is recommended that the minimum fill depth should be not less than 200mm or one fifteenth of the internal width of the culvert if this is greater.