Effect of connection flexibility on fire resistance of steel beams

The structural behaviour in fire of simple substructured frames consisting of unprotected steel I-beams and columns, which connect through a simple bolted connection, is studied using finite element modelling, Different types of connections are examined. These connections are considered as 'simple' under normal conditions. When the frame is, subjected to fire condition, two possible beneficial effects of these connections are investigated, which are the transfer of moment from the mid-span of the beam to the connection and the actual moment of resistance of the connection at elevated temperature. The former effect is more significant when the top flange has a smaller heating rate than the bottom flange in the beam. Composite action between concrete floor slab and steel beam is not included. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.