This paper explains the context of robustness of steel framed structures in fire and recommends that for very important building structures

design for fire safety should include provision for accidental damages which are not considered in normal Fire Limit State design.It identifies different modes of accidental damage and possible means of ensuring structural safety.The main part of this paper is about how to utilise catenary action in beams

which is an alternative load-carrying mechanism to bending

to redistribute loads from damaged structural members to the rest of the structure.To enable substantial catenary action to develop in steel beams

it is most important to ensure the joints to possess sufficient tension resistance and rotation capacity.This paper presents an order-of-magnitude analysis of the required joint rotation capacity and some experimental evidence of the available rotation capacity of common steel beam-column joints used in the UK.Some of the more ductile joints possess significant rotation capacity at elevated temperatures（about 10°）

but even this is not sufficient for the required rotation capacity（>15°） to allow full development of catenary action when the steel temperature is very high.This paper then discusses how joint rotation capacity may be increased

including using inherently ductile joint components （for example introducing a reverse channel）

improving joint detailing such as moving the joint tension components closer to the compression components and using slotted holes for bolts)

and selecting stronger and ductile bolts made of Fire Resistant steel.Many of these proposed joint technologies may compromise joint performance for other design requirements（for example stiffness）

and more extensive research is necessary to find optimised joint solutions that are able to meet the different requirements of structural performance.