introduCtion ConCrete pipe stormwater treatment teChnologies box seCtions Wheel Distribution of CL-800 Five-Axle Semi-Truck3 Surcharge4 When considering the loading conditions a buried structure will be subjected to, it is important to include the horizontal and vertical force effects due to footings and other loads placed in or on the backfill. As per the CHBDC, “A live load surcharge shall apply where the backfill supports highway live loads within a distance from the back face of the wall equal to the effective height. Where an approach slab extends over this distance and is supported by or at the wall, the surcharge shall not apply. The live load surcharge shall be equal to an equivalent additional fill height of 0.80 m. The surcharge shall be assumed to act above the finished grade and over the length of the retaining structure.” manhole and CatCh basin material 3 CAN/CSA S606, Canadian Highway Bridge Design Code, Canadian Standards Association and Standards Council of Canada, 2006, page 53. 4 CAN/CSA S606, Canadian Highway Bridge Design Code, Canadian Standards Association and Standards Council of Canada, 2006, page 245. LAFARGE PIPE eMANUAL PAGE 33