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The load bearing capacity of steel and concrete composite slabs using thin-walled steel sheeting with prepressed embossments is in most cases determined by its resistance in longitudinal shear. The designing of composite slabs still requires the performance of full-scale laboratory bending tests. Small-scale shear tests cannot include all of the influences affecting the bended slab but using an appropriate procedure the shear characteristics obtained from them can be used for determining the bending capacity of the slab. Two such procedures are compared in this paper.End constraints effectively increase the load bearing capacity of the composite slabs. Two different types of easily assembled additional end constraints are also tested and compared in this paper. Small-scale tests are used to obtain their shear bearing characteristics and to predict the load bearing capacity of bended slabs using these constraints.

The paper presents an experiment and a numerical analysis of a steel beam subjected to three‐point bending. The beam was connected to short column stubs by bolted end plates. The joints were designed as semi‐rigid and their influence on the lateral‐torsional buckling resistance of the beam was evaluated. The cross‐sections of the beams and the columns were IPE 180 and HEB 140, respectively. The columns were 1 m long and were rigidly connected to the loading frame at their ends. The beams were 3.3 m long and were loaded at midspan. 9 beams were tested in total, from which 3 beams were without any stiffeners, 3 beams had two inclined stiffeners welded prior to the test, and 3 beams upon which the stiffeners of the same geometry were welded under load equal to 50 % of the bending resistance of the unstiffened beam. The stiffeners were at one third and two thirds of the beam span. The experiment was modelled in software using Component‐based Finite Element Method. Shell elements were used for plates and special nonlinear springs and interpolation links for simulation of bolts and welds. Geometrically and materially nonlinear analysis with imperfections was used. The experimental results were compared to the model. A sensitivity study with various levels and kinds of initial imperfections was performed.

Composite slab is being used for horizontal structures. The sheeting can serve as a permanent formwork and no additional reinforcement can be required. The slabs are then fast and easy assemble construction which can be effectively used in reconstructions. One of the meanings to assure composite action of composite steel-concrete slabs is prepressed embossments. Its main disadvantage is that the design of a new type of sheeting requires expensive and time consuming large-scale laboratory testing which hamper its widespread commercial usage. Small-scale shear tests present a less expensive alternative to the large-scale tests but its results cannot be simply used for the design of the whole slab. The results from small-scale tests with different options are compared in this paper. Also a possibility of contribution of FE simulation results to the small-scale tests usage is investigated.