Dogodki  

Teden požarne varnosti

 

Predavanje:

Fire Resistance of Connections in Steel Structures

Prof. František Wald, Czech Technical University in Prague

 

The fire affects the structural joints by reduction of the material properties, redistribution of internal forces and non-homogenous heating of connection components. By the concentration of mass in a joint, compare to connected element, is the connection heated later compare to beam and on reverse during cooling is the temperature in connection higher compare to connected beam.

For structural steel the connections can be protected by fire protection in a similar way as the structural members, or the temperature of connections may be predicted for its mechanical analyses at high temperature by component method. The connections can be calculated using the section factor Am /V (or Ap /V) of components creating the joint, where Am is the surface area of connection exposed to heat, Ap internal area of fire protection and V the volume of joint per unit length. For beam to column connection and beam to beam connection, which is supporting the concrete slab the temperature can be predicted from the temperature of the mid span of the beam. By this model is expected that the temperature of the connection component depends on the vertical distance from the upper part of the connected beam. The influence of mass is expressed only indirectly in the prediction of the temperature of the lower flange at midspan.

 

The aim of proposed lecture is to introduce to the knowledge summarised into the EN 1993-1-2 Design of steel structures general rules, Structural fire design based on the tests on whole structure in Cardington BRE laboratory. The material will be equipped by the CD of the European project CeStruCo, which includes the video of the seventh compartment fire test on Cardington Frame and educational materials related to connection design prepared by the European project Leonardo.