| Recently, the perfobond connector was appeared as a newly developed shear connector used to connect a steel beam and a concrete deck slab in composite bridges. The behaviour of the connectors was mainly interested by several researchers. Nevertheless, the provisions available to estimate the shear resistance of this connector are rare in comparison with other types used long ago.In the present work, the push-out test is used to investigate the connector resistance capacity of both stud shear connector and perfobond shear connector. A total of 24 push-out specimens are tested to failure. The study includes investigation on the effects of stud diameter, presence of transverse reinforcement in perfobond connector ribs and method of concrete placement. The optimum choice between the parameters considered is reported and the best choice is recommended. Tests shown that, using perfobond connector would give better connection between steel beams and concrete slabs than stud connectors.Furthermore, the finite element method is used in modeling the push-out specimen, by using the commercial finite element software ANSYS. The three dimensional finite element model adopted is verified by comparing with experimental results. Material and geometrical nonlinearities are considered in the finite element analysis. Detailed investigations on the effects of modeling of nonlinear behaviour of materials used, etc. steel and concrete, are conducted. Therefore, different types of concrete nonlinear modeling options available in ANSYS software, modeling of reinforcement and the element mesh size effects are testified. The results of the developed model show that the verified finite element model has the capability to predict the complete response of push-out specimen to failure.Further studies using the verifies finite element model are conducted to investigate the behaviour of perfobond connector with the variation of height and thickness of connectors, area of transverse reinforcement passing through perfobond rib hole, the steel yield strength of reinforcement, the area of concrete dowels and the concrete compressive strength. A total of 89 models considered the above parameters are analyzed and the results treated statistically to predict expressions give the relation between the parameters, which is suggested to be used in perfobond connector's shear resistance estimation. The present work also suggests a new shape of perfobond connector. The finite element model is used to model push-out specimen with newly suggested shape perfobond connector and compared with the regular perfobond connector results. The results show that, the newly suggested connectors give an acceptable shear resistance.The verified finite element model of push-out specimen with new perfobond connectors are then used as a basic model to generate more numerical results. The effects of the height and thickness of connectors, area of transverse reinforcement passing through perfobond rib holes, the steel yield strength of reinforcements, the area of perfobond hole and the concrete compressive strength are investigated using 140 models presenting the results in terms of load-relative displacement curves and shear resistance. The results are treated statistically to obtain expressions suggested to estimate the shear resistance of connector obtained using push-out test.The sequence of failure of perfobond connector is discussed, using the results obtained by finite element method, showing that, a rotation appeared affects on shear connector resistance. The use of distributed transverse reinforcement passing through hole of newly suggested perfobond connector is shown to enhance shear resistance of the connector due to the ability of the two layers of reinforcement to resist the rotation appeared.The effect of using triangular hole perfobond connector with circular head is also investigated using finite element model. The results show that, using such type would reduce the shear resistance of the newly suggested perfobond connector and increase the relative displacements comparing with connector having normal triangular hole heads.The numerical expression suggested to be used in shear resistance calculations for both regular shape perfobond connectors and newly suggested shape perfobond connectors are summarized. The expression is suggested to be used within the limits of the present study explained in details. |
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