Civil Engineering / İnşaat Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/13
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Conference Object Behavior and Modeling of Shear-Critical Rc Beams Under Impact Loading(American Concrete Institute, 2010) Saatçi, Selçuk; Vecchio, Frank J.The lack of a complete understanding of shear behavior under high dynamic conditions hindered the efforts for accurate prediction of impact behavior, since severe shear mechanisms may dominate the behavior of RC structures when subjected to impact loads. This current study involves a well-instrumented experimental program that was undertaken to contribute to our understanding of the effects of shear mechanisms on the behavior of reinforced concrete (RC) structures under impact loads. The test results showed that the shear characteristics of the RC beam specimens played an important role in their overall behavior. All specimens, regardless of their shear capacity, developed severe diagonal shear cracks, forming a shear-plug under the impact point. Furthermore, the application of the Disturbed Stress Field Model (DSFM) as an advanced method of modeling shear behavior under impact conditions is also investigated. A two-dimensional nonlinear finite element reinforced concrete analysis program (VecTor2), developed previously for static loads, was modified to include the consideration of dynamic loads such as impacts. VecTor2 analyses of the test specimens were satisfactory in predicting damage levels, and maximum and residual displacements. The methodology employed by VecTor2, based on the DSFM, proved to be successful in predicting the shear-dominant behavior of the specimens under impact.Article Citation - WoS: 277Citation - Scopus: 345Effects of Shear Mechanisms on Impact Behavior of Reinforced Concrete Beams(American Concrete Institute, 2009) Saatçi, Selçuk; Vecchio, Frank J.A well-instrumented experimental program was undertaken to contribute to our understanding of the effects of shear mechanisms on the behavior of reinforced concrete (RC) structures under impact loads and to provide data for verification of methods developed for the impact analysis of such structures. Eight RC beam specimens, four pairs, were tested under free-falling drop-weights, impacting the specimens at the midspan. All specimens had identical longitudinal reinforcement, but varying shear reinforcement ratios, intended to investigate the effects of shear capacity on the impact behavior. A total of 20 impact tests were conducted, including multiple tests on each specimen. The test program was successful in providing a substantial amount of high-quality impact test data. The test results showed that the shear characteristics of the specimens played an important role in their overall behavior. All specimens, regardless of their shear capacity, developed severe diagonal shear cracks, forming a shear-plug under the impact point. © 2009, American Concrete Institute.Article Citation - WoS: 78Citation - Scopus: 88Nonlinear Finite Element Modeling of Reinforced Concrete Structures Under Impact Loads(American Concrete Institute, 2009) Saatçi, Selçuk; Vecchio, Frank J.The methods available in the literature for the analysis of reinforced concrete (RC) structures subjected to impact loads generally exhibit some deficiencies in aspects relating to applicability, practicality, and accuracy. The shear-dominant behavior of RC members under impact loads creates another significant shortcoming, because modeling the shear behavior of RC has long been a challenging issue. This study aims to present and verify a nonlinear finite element analysis procedure employing the Disturbed Stress Field Model, based on a smeared rotating crack approach, as an advanced method of modeling shear behavior under impact conditions. The proposed methodology has a wide range of applicability, and displays fast solution time while providing extensive and accurate information on structural behavior. The methodology was tested by analyzing a set of RC beams subjected to impact loads. A high level of accuracy was demonstrated in various comparisons between test and analysis results, including peak and residual displacements, crack profiles, and reinforcement strains.