Timber-concrete composite (TCC) solutions are not a novelty. They were scientifically referred to at the beginning of the 20th century and they have proven their value in recent decades. Regarding a TCC floor at the design stage, there are some assumptions, at the standard level, concerning the action of concentrated loads which may be far from reality, specifically those associating the entire load to the beam over which it is applied. This naturally oversizes the beam and affects how the load is distributed transversally, affecting the TCC solution economically and mechanically. Efforts have been made to clarify how concentrated loads are distributed, in the transverse direction, on TCC floors. Real-scale floor specimens were produced and tested subjected to concentrated (point and line) loads. Moreover, a Finite Element (FE)-based model was developed and validated and the results were collected. These results show that the “loaded beam” can receive less than 50% of the concentrated point load (when concerning the inner beams of a medium-span floor, 4.00 m). Aiming at reproducing these findings on the design of these floors, a simplified equation to predict the percentage of load received by each beam as a function of the floor span, the transversal position of the beam, and the thickness of the concrete layer was suggested.
The paper presents a simplified method for calculation of resistance of a TCC slab in fire conditions. Within the method the tensile and the compressive failure criteria in the outermost fibres of the cross-section are checked. The influence of the fire is applied through one-dimensional charring of the timber part of the cross-section in accordance with current standards on reduction of properties of materials. The concrete-timber connection is assumed to be ideal during the determination of resistant moment of the TCC cross-section. On the other hand, the calculation of the deflection of the TCC slab is conducted with the reduction of the connection’s rigidity. The ineffective zone of the timber as well as the cracked tensile zone of concrete part do not contribute to the effective stiffness of the TCC slab. The method is validated against the results of full sized fire tests of one way spanning TCC slabs form literature. Calculated and experimentally determined midspan deflections and failure times of the TCC slabs are compared and their considerable agreement is observed. Due to its convenience and accuracy, the present simplified method represents a useful tool for designers of TCC structures in fire conditions.