Query : There seems to be problem in classification of the angle section. The double angle section is classified as slender and consequently it is failing. However the if the same member is replaced with single angle, it is passing. the STAAD file is provided below.
STAAD SPACE START JOB INFORMATION ENGINEER DATE 10-Apr-08 END JOB INFORMATION INPUT WIDTH 79 UNIT CM KG JOINT COORDINATES 1 0 0 0; 4 312.501…