Behavior of prefabricated reinforced concrete purlins having web openings under vertical loads

Purlins are used in prefabricated building systems in order to pass the openings between the roof truss or porch beams, to connect the main carrier elements of the roof system and operate them together, and to transfer dead loads such as the coating that the roof system will carry to the main carrier elements of the roof. Considering that the purlins used are found in large quantities in prefabricated building projects, it is thought that the gaps to be created in the high bending regions of these beams and at the midpoint of the body can save especially from the production material, concrete. Based on this basic idea, in the thesis study, the changes in the load-bearing capacity and ductility of the purlins were experimentally analyzed by applying seven different sizes of void forms with a fixed height of 8 cm and a length of 24, 40, 56, 72, 3x24, 88 and 104 cm in both prestressed and non-prestressed purlins. examined. A total of 16 purlins produced were subjected to a four-point bending test with a shear opening (av/d) of 3.58. As a result of the experimental study, it was observed that there was no significant change in the bending capacity of purlin beams compared to the reference beams, but the ductility increased with the increase in voids and void size. In non-prestressed and prestressed purlins, voids longer than 25% of the beam length revealed significant crushing damage in the compression region. The spreading behavior towards the shear region was observed in bending damages with increasing gap length. Unlike the prestressed beams, in the non-prestressed purlin beams, which theoretically have a total bearing capacity of 30% of the prestressed purlins, a more significant increase in the load bearing capacity in the linear elastic region has been observed. In terms of energy consumption capacity, while the increased gap size in non-prestressed beams increases total energy consumption and elastic energy consumption, a significant decrease in energy consumption, especially in the linear elastic region, was observed in 88 and 104 cm long gaps in prestressed beams.