The structural behavior of timber-concrete composite slabs is mainly governed by the shear connection between timber and concrete. When a timber-concrete composite structure is exposed to fire, it is of particular importance to know the changes in stiffness and strength that the shear connection is subjected to. For the calculation of the fire resistance of timber-concrete composite slabs a simplified design method was developed on the basis of the calculation model for mechanically jointed beams with flexible elastic connection given in EN 1995-1-1 and the reduced cross section method given in EN 1995-1-2. The effects of temperature on the mechanical properties of timber, concrete, and connection are taken into account by modification factors kmod,fi . For the strength and stiffness properties of the screwed connections simplified formulae for the calculation of the modification factors kmod,fi were developed, based on the results of an extensive experimental study on the fire behavior of the screwed con...