[API CODE] ask : RATIO command

dear all.

i want to ask about the RATIO command in API code in Staad pro v8i.

i use Staad Pro v8i SERIES 4. in AISC, the RATIO command means "Permissible ratio of actual to allowable stress". but in API, it says "Permissible ratio of applied loading to section capacity".

AISC

API

i did study to compare using the RATIO command under API code. 

case 1 : i use RATIO 2.06

Section Member Actual Allowable Normalized LC Param. Notes
Properties ID Max. Ratio Ratio Max. Ratio      
PIP1500X50 1 0.923 2.060 0.448 5006 13 API 3.3.1-2
PIP355.6X12 2 3.113 2.060 1.511 5008 13 API 3.3.1-1


case 2 : RATIO 1 (default)

Section Member Actual Allowable Normalized LC Param. Notes
Properties ID Max. Ratio Ratio Max. Ratio      
PIP1500X50 1 0.923 1.000 0.923 5006 13 API 3.3.1-2
PIP355.6X12 2 51.219 1.000 51.219 5026 13 API 3.3.1-1

it's the same staad file. but when i change the RATIO to default, the actual ratio shows totally different from case 1.

anyone know why this is happen ?

basically if i use the RATIO command under AISC code, it won't show any different actual ratio. only the normalized ratio.

thank you.

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