Stress and shear of steel reinforced floors with prefabricated units and steel beams

Steel-reinforced concrete floors with prefabricated reinforced concrete slabs are industrial quickly erectable structures. The use of such structures makes it possible to reduce construction time, save metal, obtain efficient structures without beam projecting up to 20 m for loads produced by buildings and car parks. Codes and foreign norms do not include prefabricated reinforced concrete floor slabs in the operation of combined structures, as designers try to avoid complex connections (welding, bolts) during construction. Of obvious interest is the inclusion of precast slabs in the operation of combined steel and reinforced concrete beam as well as grouted joints between steel and slabs in the absence of additional anchors and connections.

Experimental results of structural models and 6×10 m floors with precast slabs are considered to identify the concrete shear. The effective shear deformation up to 0.5 mm is detected even without additional anchors. Simplest anchors significantly increase the joint operation of cast concrete and steel profile. The operation mechanism is determined for steel-concrete and steelconcrete-anchor contact zones, and respective diagrams are plotted for numerical calculations.

Floor testing shows that the use of the simplest joining, cast reinforced concrete combining steel and precast elements involves precast slabs at a distance from the beam axis of at least two thicknesses of the floor for two different ways of the beam support.

Numerical modelling, including the contact zone operation, shows good agreement with the experimental data. It is recommended to clarify the width of compressed concrete flange in normative documents for the structural analysis.

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