Abstract:A new method of load reduction by reinforcement bridge for highway culvert beneath high filling is presented in the paper. According to this method and the principal of load reduction by reinforcement bridge,a “reinforcement bridge”which is consist of reinforcements and a load reduction ditch filled with unpacked soil is built above the culvert to reduce the earth pressure on it. Because the density of soil in the ditch is lower compared to the earth filled on the culvert,the reinforcements on the ditch will deflect down,and in the course of reinforcements deflecting,the vertical earth pressures are transported to the packed soil around the ditch by the reinforcements,as a result,the earth pressures on the top of culvert are reduced. The results of model test show that the vertical earth pressures on the top of culvert with reinforcement bridge are greatly reduced. The results also indicate that the distribution and numbers of reinforcement and load reduction ditch are important factors which affect on the effect of load reduction. Based on the mechanics mechanism of load reduction by reinforcement bridge and the results of model test,a mechanics model of load reduction by reinforcement bridge is presented and three important formulas,including the formula of load calculation,the formula of the numbers and length of reinforcements calculation,are derived from the mechanics model,and an example is given. To prove the effect of load reduction by reinforcement bridge in practice,the stresses of a concrete slab culvert are tested in field and the good load reduction effect is confirmed by the field test results. The results of model and field culvert testing demonstrate that the method of load reduction by reinforcement bridge can be used to highway culverts and other pipes beneath high filling.