D. Allowable bearing capacity estimation
(1) Allowable bearing capacity is limited by and related to preset settlement
or differential settlement criteria.
(2) Earth walls integrated with wider flexible bases are allowed higher bearing
capacity and tolerate more settlement than rigid walls on spread footings.
E. Allowable differential settlement
(1) Settlement is a time-dependent behavior.
(2) Top-of-wall settlement is a sum of settlement from wall and from subsoil
strata.
(3) Allowable settlement should be evaluated by considering tolerable movement
of superstructure and wall precast facings.
(4) Simple-span bridges tolerate more angular distortion between adjacent
footings than continuous-span bridges.
(5) Tolerable (vertical and horizontal) movement of a wall facing is a function
of panel joint width and pattern of connection