Browsing by Author "Batarlar, Baturay"

Now showing 1 - 2 of 2

Behavior of reinforced concrete slabs subjeted to impact loads
(Izmir Institute of Technology, 2013) Batarlar, Baturay; Saatcı, Selçuk
This study presents the findings of an experimental program designed for investigating the behavior of RC slabs under low-velocity impact loads. Six RC slabs with dimensions 2015x2015x150 mm were tested at the Structural Laboratory of the Izmir Institute of Technology. To facilitate a comparison between the static and impact behavior of identical specimens, the slabs were cast in three identical pairs, such that one of the specimens was tested under impact loads whereas its identical twin was tested under static loads. To test the slabs under simply supported conditions, an innovative impact test setup was designed and manufactured, supporting the specimens at 20 locations along the perimeter and holding the specimens in place during the impact induced rebound. This setup was also used for the testing of the specimens under monotonically increasing static loads at the midpoint. Impact loads were induced on the specimens by a free falling drop-weight, impacting the specimens at the midpoint. The specimens were intensely instrumented with 20 load cells at each support location, 24 displacement transducers, 6 accelerometers and 12 strain gauges fixed to the reinforcing bars. Dynamic data was captured with the help of a high speed data acquisition system, capturing and recording the data at a rate of 250 kHz per channel. The results obtained from these tests revealed that the impact behavior of slabs differs significantly compared to their static behavior. Displacement profiles and force distributions are highly affected due to the high inertia forces during the impact.
Impact behavior of textile reinforced concrete slabs
(Izmir Institute of Technology, 2021-03) Batarlar, Baturay; Saatçi, Selçuk
Reinforced concrete (RC) technology is still the most preferable and common method to build civil engineering structures. In accordance with design purposes and needs, these structures are built to resist various loading scenarios. Throughout the lifespan of RC structures, they may be subjected to high rate loading scenarios due to either expected or unexpected reasons such as impacts caused by vehicular collisions, debris generated by typhoons, tsunami or floods, rock or object falls to protective shelters. Therefore, understanding of impact behavior of RC members plays a vital role not only for design stages but also retrofitting and strengthening purposes thereafter. For this purpose, an experimental program was carried out to reveal the impact behavior of RC slabs strengthened with carbon textile reinforcements. In this program, four slabs specimens, two unstrengthened and two strengthened with two different carbon textile reinforcements, having dimensions of 1.5 m × 1.5 m × 0.2 m were tested by using an advanced impact testing facility at Otto-Mohr Laboratiorum of Technische Universität Dresden. In these tests, all slabs were tested under repeated impact loads by using the same steel striker with a 200 mm - diameter flat contact surface in the velocity range of 25.2 to 30.2 m/s. The results obtained from these tests are presented in terms of midpoint-displacement histories, reaction force histories, slab accelerations, and strain histories of steel reinforcements for each impact. As a result of the test program, it is shown that carbon textile reinforcements have significant effects on enhancing impact capacity as well as limiting maximum and residual midpoint displacements. By using the data obtained from tests, a finite element (FE) modeling study was performed by using the LS-DYNA software tool. In this study, two FE models with different mesh sizes were created and compared with each other to obtain efficient modeling conditions. In the light of the tests and validated models, a parametric study was performed to figure out efficient impact conditions and parameters for carbon textile reinforcements. It is shown that carbon textile reinforcements are more effective for limiting damage levels under low-velocity impacts.