Introduction

Although EC2 gives information on how to identify a sway structure, it does not give any simple approach to their design. However, Clause A.3.5.(2) states that "the simplified methods defined in 4.3.5 may be used instead of a refined analysis, provided that the safety level required is ensured". Clause A.3.5(3) amplifies this slightly, saying that "simplified methods may be used which introduce bending moments which take account of second order effects

provided the average slenderness ratio in each storey does not exceed

50 or 20//F; whichever is the greater".

EC2 Section 4.3.5 gives the 'model column' method which is developed only for non-sway cases, so it is left to the user to find a suitable method for sway frames on the basis of the Model Column Method. BS 8110 does this, so it is suggested that the provisions of 3.8.3.7 and 3.8.3.8 of BS 8110: Part 1 are adopted, but that the eccentricities are calculated using the equations in EC2.

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