A simple approach for the design of steel and composite sway building frames

The Merchant-Rankine approach is a practical design procedure which allows to predict the ultimate resistance of sway steel building frames with rigid structural joints. In the present paper the background and the traditional field of application of the Merchant-Rankine formula are first described. Its extension to the design of steel frames with so-called semi-rigid joints is then presented and justified. Finally its application to steel-concrete sway composite building frames is investigated and first conclusions of this work are drawn.