Browsing by Author "Erol, Hakan"

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Investigation of Low-Velocity Impact Behavior of Two-Way Rc Slab Strengthening With Basalt Trm Strips
(Springernature, 2023) Erol, Hakan; Şengel, Hasan Selim; Yılmaz, Tolga; Anıl, Özgür; Unalan, Mehmet Enes
Reinforced concrete (RC) structural members could be subjected to impulsive impact loads due to various effects such as the collision of masses driven by rockfall, flood, landslide, avalanche, the crash of vehicles to structural elements in highway and seaway, airplane landing contact, the acting of explosion-induced air shock waves on structural elements as impulsive loads. The conventional design of RC slabs and similar structural members is carried out regarding vertical static and lateral dynamic loads such as earthquake and wind effects. However, the design phase mostly ignores impulsive loads such as impact and blast. Thus, these effects pose risks that the structures experience heavy damage or total collapse. Strengthening RC slabs with textile strips has become a preferred strengthening technique to prevent the collapse of structures and limit damage to structural elements. This study strengthened RC slabs with basalt textile reinforced mortar (TRM) strips in different widths, and layout patterns were tested for low-velocity impact load. In addition, the effects of BFRP fan-type anchors near the impact point on the behavior have also been investigated. The effect of various applied strengthening patterns on impact load transferred to specimens, dynamic responses such as acceleration, displacement, maximum strain, and dynamic failure modes occurred were investigated and interpreted in detail. The experimental results have also been compared with the improved finite element model (FEM) generated. It is demonstrated that the present FEM can be used to evaluate the impact response of the RC slabs with TRM strips.
Citation - WoS: 35
Citation - Scopus: 36
Investigation of the Effects of Impactor Geometry on Impact Behavior of Reinforced Concrete Slabs
(Elsevier Sci Ltd, 2022) Şengel, Selim; Erol, Hakan; Yılmaz, Tolga; Anıl, Özgür
One of the important parameters that affect the behavior of the reinforced concrete (RC) members under impact loading is the impactor geometry used for applying impact loading. It is known that changes in the impactor geometry have significant effects on energy transfer to the structural system, deformation distribution, and damage on structural members caused by impact loading. However, there is no encounter with a study with a detailed and comprehensive conclusion on this topic during the literature review. The lack of this kind of conclusion leads to an experimental study with different impactor geometries applying impact loading on RC slabs. These experiments examine the effects of impactor geometry on acceleration-time, displacement-time, impact loading-time, and maximum strain-time behaviors. In addition to those, effects on damage distribution and impact loading behaviors are examined. This study uses three flat-surfaced hammers with different surface areas and a hemispherical hammer. Impact loading is applied at two different magnitudes on specimens. Ls-Dyna software is also used to do numerical analysis for the members. Outputs of the analysis are compared with the experimental results to evaluate the modeling of effects of change in impactor geometry. When the results obtained as a result of the experimental study were examined, it was seen that the change in the geometry of the impactor to which the impact loading was applied significantly changed the behavior of the slabs under the impact loading. The increase in the impactor contact area caused an increase in the impact loading applied to the specimens, and the acceleration, displacement, residual displacement, and strain values measured from the specimens all increased.
Citation - WoS: 2
Citation - Scopus: 2
Investigation of the Effects of Shear Reinforcement Ratio and Opening Size on the Impact Behavior of Rc Beams Produced With Geopolymer Concrete
(Elsevier Science inc, 2025) Erkan, I. Hakki; Aslan, Salih; Erol, Hakan; Sengel, H. Selim; Yilmaz, Tolga; Arslan, M. Hakan; Anil, Ozgur
Investigations have revealed that construction, manufacturing, and the construction sector collectively account for a significant proportion of global energy consumption and emissions. The issue of climate change has become a matter of significant concern, with the slowing down of problems caused by it and the prevention of some of them before they occur occupying a prominent position on the global agenda. Concrete remains the most prevalent building material globally. The primary component of concrete utilized in its production is cement. However, cement is a building material that requires significant energy inputs during manufacture and generates substantial carbon emissions. Consequently, research on environmentally benign alternative concrete formulations that can be produced using alternative binding agents and recycled waste materials instead of cement has witnessed a gradual surge. Research on geopolymer concrete, one of these types, has intensified increasingly in the last decade. Research investigating the behavior of reinforced concrete structural elements produced using geopolymer concrete under static and cyclic earthquake loading has gradually increased in the literature. However, a literature review reveals a paucity of studies examining the behavior of reinforced concrete (RC) members produced using geopolymer concrete under sudden dynamic loading, such as that caused by impact forces. For this reason, an experimental study was planned, and 16 RC beams produced using standard concrete and geopolymer concrete, without and with circular web openings of different sizes, with insufficient and sufficient shear strength, were tested under impact loading using a drop weight test setup. Under the effect of constant energy level impact loading applied to the specimens, the variations of acceleration, displacement, and impact loading values for time were measured, general impact behavior, failure mechanisms, and energy dissipation values were calculated and interpreted, and it was investigated how they were affected by the experimental variables examined in the study. The openings in the RC beams and the increase in the size of the openings negatively affected the performance of all beams under impact loading. In addition, the RC beams tested in the experimental study were modeled using Ls-Dyna finite element software. The values obtained from the numerical analysis were compared with the experimental results, and the extent to which successful analyses could be performed was interpreted.
Citation - WoS: 13
Citation - Scopus: 13
Low-Velocity Impact Behavior of Two-Way Rc Slab Strengthening With Carbon Trm Strips
(Elsevier Ltd, 2022) Şengel, Selim; Erol, Hakan; Yılmaz, Tolga; Anıl, Özgür; Can Gürdal, H.; Muhammed Uludoğan, A.
Sudden dynamic impact loading on reinforced concrete (RC) slabs due to reasons such as the impact of debris due to landslide or rock fall, the impact of drifting objects due to effects such as flood or tsunami, the impact of vehicles on highway or seaway bridges, the impact of air shock waves due to explosions inside or outside of structures may lead damage and collapses. This study is aimed to examine the behavior of RC slabs reinforced with Textile Reinforced Mortar (TRM) strips, which have been used in reinforcement applications for the last ten years, under the effect of sudden dynamic impact loading. The variables examined in the experimental study are the TRM strip width, the placement of the strips, and whether the anchors are present on the strips or not. The acceleration-time, displacement–time, strain–time over the strips, and applied impact loading-time distributions are measured and interpreted under the effect of impact loading with a constant energy level applied by the drop-weight system. In addition, numerical analysis of the slabs is done with Ls-Dyna software, compared with the experimental results, and examines how successful the analysis results are. The reinforcement technique applied with TRM strips developed within this study's scope significantly increased RC slabs' performance under impact loading. The TRM strips used for strengthening in both directions were the variable that had the most positive effect on impact behavior. Increasing the strip width and anchoring followed the use of double directional strips in improving performance under the impact loading. © 2022 Institution of Structural Engineers
Citation - WoS: 2
Citation - Scopus: 3
Low-Velocity Impact Behavior of Two-Way Sfrc Slabs Strengthened With Steel Plate
(Springernature, 2024) Al-Hagri, Mohammed Gamal; Döndüren, M. Sami; Yılmaz, Tolga; Anıl, Özgür; Erol, Hakan; Şengel, Hasan Selim
Structural systems and structural elements can often suffer severe damage or even completely collapse under the effect of sudden dynamic impact loading, which is a different type of loading that is not considered during their design. Research on how structures behave under impact loading and how they can be strengthened to perform better against this type of loading has increased to avoid such undesirable severe damage. Within the scope of this study, it is aimed to improve the behavior and increase the performance of two-way steel fiber-reinforced concrete (SFRC) slabs, one of the leading structural elements that can be affected by impact loading, using steel fiber concrete (SFC) and placing steel plates on the surface of the RC slab. Within the scope of the study, the effects of placing FRC as layers in different positions within the slab and placing the steel plate on different surfaces of the slabs were examined. Impact loading was applied using a drop weight test setup designed by the authors, and the acceleration-time, displacement-time, and impact loading-time behaviors of the RC slabs were measured and interpreted. The use of fiber concrete in RC slabs and strengthened with steel plates increased the maximum acceleration values by an average of 3% and 113%, respectively. The use of fiber concrete in RC slabs reduced the maximum displacement and residual displacement values by an average of 2% and 25%, respectively. Placing steel plates on the slabs reduced the maximum displacement and residual displacement values by an average of 270% and 199%, respectively. In addition, the energy absorption capacities of RC slabs were calculated, and how they were affected by experimental variables was examined. Numerical analyses of the RC slabs tested in the study were also conducted using ABAQUS finite element software, and the results obtained were compared with the experimental ones.