EX E ▁method ▁ ▁Short ly ▁after ▁the ▁end ▁of ▁the ▁Second ▁World ▁War ▁the ▁establishment ▁developed ▁the ▁M EX E ▁method ▁as ▁a ▁means ▁of ▁quickly ▁assess ing ▁the ▁carrying ▁capacity ▁of ▁arch ▁brid ges , ▁particularly ▁for ▁military ▁traffic . ▁ ▁The ▁method ▁was ▁developed ▁by ▁Alfred ▁Pi pp ard ▁of ▁Imperial ▁College , ▁London . ▁ ▁The ▁bridge ' s ▁span , ▁arch ▁thick ness ▁and ▁depth ▁of ▁fill ▁were ▁input ▁into ▁an ▁equation ▁or ▁nom ogram ▁to ▁determine ▁a ▁prov is ional ▁acceptable ▁ax le ▁loading . ▁ ▁This ▁was ▁then ▁modified ▁by ▁a ▁number ▁of ▁additional ▁factors ▁to ▁determine ▁a ▁maximum ▁perm iss ible ▁loading , ▁which ▁could ▁be ▁used ▁to ▁assess ▁which ▁military ▁vehicles ▁could ▁use ▁the ▁bridge . ▁ ▁It ▁was ▁a ▁quick ▁and ▁simple ▁process ▁but ▁provided ▁no ▁assess ment ▁of ▁the ▁actual ▁str esses ▁or ▁def lections ▁of ▁the ▁bridge . ▁ ▁It ▁was ▁later ▁adapted ▁to ▁civil ian ▁use . ▁ ▁M EX E ▁pro be ▁The ▁M EX E ▁pro be , ▁also ▁known ▁as ▁the ▁So il ▁Ass ess ment ▁C one ▁Pen et rom eter ▁or ▁M EX E ▁C one ▁Pen et rom eter , ▁is ▁a ▁piece ▁of ▁equipment ▁developed ▁by ▁M EX E ▁to ▁estimate ▁the ▁California ▁bearing ▁ratio ▁( C BR ) ▁of ▁a ▁sub grade ▁( so il ) ▁in ▁the ▁field . ▁ ▁It ▁is ▁a ▁pointed ▁cone ▁attached ▁to ▁a ▁spring - loaded ▁handle ▁by ▁extension ▁sp ind les . ▁ ▁The ▁device