Experimental study on the longitudinal shear transfer mechanisms and resistance in CSTC composite beams

On the load‐carrying behaviour of CSTC slim‐floor beams

“…The peculiar geometry of the NPS beams described in the previous section allows refraining from dedicated shear connectors as the sinusoidal structural steel bars are responsible for transferring the vertical shear forces (as in a typical truss system) and the longitudinal shear forces into the surrounding concrete simultaneously. Whilst the potential issues arising from the interaction between vertical and longitudinal shear forces have been numerically tackled in [4], the longitudinal shear transfer was investigated experimentally by means of a wide push-out test campaign consisting of a total of 43 push-out tests [5,6]. It is worth mentioning that past experimental and numerical studies focused mostly on CSTC beams using reinforcement steel bars [7,8,9], in some cases with relatively small diameters (lower than 18 mm) [10,11], rather than structural steel bars.…”

“…The experimental campaign presented in [5] provided the basis for the development of the equations for predicting the design resistance of the equivalent shear connector but the local stress field of the waveform bars was sensed via strain gauges at predefined locations. However, the whole strain field in the embedded steel diagonals during the tests remained unknown and more advanced measurement techniques are required to overcome this issue.…”

“…η>1.0. Based on the push-out tests on this type of beams and the analytical formulation [5], the D20 and D32 beam types have an expected shear connector force capacity of 265 kN and 675 kN, respectively. This leads to nominal shear connection values η of 1.92 and 2.68 for these two beams and allows to conduct the cross-sectional analysis within the restrictions of the strain-limited analysis procedure, but without further consideration of the shear connector limit states.…”