Discussion

The results obtained in Sections 5.6.4.1 and 5.6.4.2 above are totally illogical as the structure has been shown to be a sway structure in the stiffer direction and non-sway in the less stiff direction.

There are two possible areas where the drafting of EC2 is ambiguous and the wrong interpretation may have been made.

(1) In Eqn A.3.2 it is specifically stated that the height should be in metres. Nothing is stated about the units for /c, Fv and Ec. Since the output from Eqn A.3.2 is non-dimensional, the statement of the units is unnecessary unless the units for I, F and E are different to that for h... Should I, F

and E be in N and mm units while h,, is in m? If this were so, then the c tot '

structure would be found to be 'braced' by a large margin.

(2) In A.3.2(3) it does not state whether X should be calculated assuming the columns to be sway or non-sway. In the calculation, the assumption was made that the X was a non-sway value. If a sway value had been adopted, the structure would have proved to be a sway frame by a considerable margin.

Clearly, clarification is required if A.3.2 is to be of any use at all.

It is possible to take this question slightly further and make some estimate at what the answer should have been.

Considering the y direction, the ultimate curvature of the section of the 750 x 450 columns is

Inspection of the design charts and levels of loading suggest K is likely to be about 0.6. Assuming an effective length under sway conditions of twice the actual height gives a deflection of:

0 0

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