ABSTRACT:In this paper, we present the results of experimental study and finite element modeling of the push-out tests on a new shear connector of I-shape. 24 push-out specimens with I-shape shear connectors were tested under a static loading in the Laboratory of Materials and Mechanics of Structures -LMMS at the University of M'sila, Algeria. The test specimens were designed to study the effect of the following parameters on the ultimate load capacity: the height of I-shape connector, the length of I-shape connector, the compressive strength of concrete and the number of transverse reinforcing bars. The load capacity, the ductility and the modes of failure were presented and discussed. Furthermore, a finite element modelling of the push-out tests was carried out using ANSYS software to investigate the stress distribution pattern in the area of the I-shape connector. Moreover, the finite element model was also used to simulate another type of shear connector, called channel connector in order to compare its behaviour with that of the I-shape connector. From this comparison, we suggested an equation for the prediction of the ultimate load capacity of I-shape shear connectors.

No abstract

In a steel-concrete composite beam, the channel shear connector is an easy solution to ensure the connection due to its availability and the simplicity of its welding. However, increasing the channel shear connector length negatively affects the concrete slabs and creates difficulties to cross the longitudinal reinforcing bars. To solve this problem, five new channel shear connector shapes are proposed and studied in this paper. Twelve push-out tests using a new setup, and three pull-out tests, were carried out under monotonic loading to identify the shape that gives the best performance. The failure modes, the effects of new channel shapes on the load-slip behavior, the concrete slaps, the bending deformation, and the height between the two plastic hinges that appeared near the base of channel connectors were mainly studied. The study reveals that the modification of the channel shear connector shape is a promising way and positively influences the concrete-connector relationship and also the bending deformation capacity of the channel connector. As a result, the concrete cracking decreased, the ductility increased between about 15-31%, and the ultimate strength improved slightly between about 0-5.1%. Finally, the experimental results are compared to the existing equations.

In the design of steel or composite structures, the connections are usually considered infinitely rigid or perfectly pinned. However, the real behavior of these connections is semi-rigid. Consequently, this semi-rigidity can influence the overall behavior of the composite structures, especially the moment-resisting frames. Seismically, the most critical parameter that characterizes the frames behavior is the response factor R. In this context, the research work consists of studying the semi-rigidity effect of the connections on the behavior of the composite frames by evaluating the response modification factor R by using the Pushover method. To accomplish this task, three types of portal frames of 3, 4 and 5 storeys were analyzed for different degrees of connection (beam-column). An easy and practical solution has been proposed to determine the approximate value of the coefficient behavior R for the composite frames with semi-rigid connections.