.If you want to design an abutments and retain walls ,one of the important issues in designing these structures for bridges is how to consider surcharging the live load. In this essay, we check out three kinds of codes related surcharge live load
In BS code .for live surcharge ,four types of conditions are considered ,for example in HA loading ,normal traffic in the United Kingdom is represented 10 KN/m2 considered
Based on the AASHTO Standard , the amount of surcharge live load depends on the position of the live_ load on top of these structures ,If a live load can be located within a horizontal distance
equal to one half the height of the structure, A surcharge pressure equal to not less than 2 feet of earth must be added to the pressure. And Also ,if the approach slab is considered We can ignore the surcharge effect
The same approach was used with AASHTO LRFD ,but the amount of this load depends on the height of the wall .In figure4 ,it shows the equivalent height of soil for vehicular load.
According to AASHTO LRFD ,if the vehicular loading is transmitted through structural slab ,which is also supported by means other than earth ,a corresponding reduction in the surcharge loads may be permitted.
,In this issue ,it is not clear what amount of reduction should be applied