Extensible Reinforcements - Active Earth Pressure
is considered in the calculation of for extensible reinforcements (Standard - , AASHTO - Extensible, FHWA NHI-10-024).
The program allows to multiply the calculated kr/ka (according to the AASHTO standards). Recommended values are shown in the following picture.by coefficient
Variation of the coefficient of horizontal stress ratio kr/ka with depth for extensible reinforcements
AASHTO LRFD Bridge Design Specifications 2004 (SI).