Applies To
	Product(s):	STAAD.Pro
	Version(s):	All
	Environment:	N/A
	Area:	Steel Design
	Subarea:	BS 5950-1:2000
	Original Author:	DSANJU, Bentley Technical Support Group

Please consider design output for member 143. The critical ratio is reported as 0.524, but "critical loads for each clause check" shows that the ratio is 0.75 due to BS 4.8.3.3. We are worried that the highest ratio is not reported as the critical clause.

The program would take the minimum ratio from clauses 4.8.3.3.1, 4.8.3.3.2 and App. I.1 and compare it with the values of the ratios for the rest of the clauses that are checked. Thus, it takes the ratio as 0.484, which has been reported for App. I.1 and compares it with the ratios for the rest of the clauses. This is because the program takes the default value of zero for a parameter called ‘ESTIFF”. To take the maximum ratio to be selected from the above three clauses (4.8.3.3.1, 4.8.3.3.2 and I.1) and compared against the rest of the ratios a value of 1 should be specified for the “ESTIFF” parameter. Try specifying this (ESTIFF 1.0) for member 143 and you will find that the critical ratio is reported as 0.754.

ESTIFF 0 would mean the minimum value among 4.8.3.3.1, 4.8.3.3.2 and App. I.1 is selected.

ESTIFF 1.0 would mean the maximum value among 4.8.3.3.1, 4.8.3.3.2 and App. I.1 is selected.

As all of the aforementioned clauses are alternatives to assess the same situation of "Compression + Bending", the default value of ESTIFF 0 provides an option of using the least ratio among these three clauses.