Evaluation of the Performance and Ductility Index of Concrete Structures Using Advanced Composite Material Strengthening Methods

Abstract

The performance of concrete structures deteriorates over time. Thus, improving their performance using fiber-reinforced polymers (FRPs), PS strands, and various strengthening methods is important. Reinforced concrete (RC) and prestressed concrete (PSC) structures develop initial cracks in concrete during bending tests, and destruction occurs over a certain period of time after a certain load is generated, and then after the reinforcements and strands yield. However, in the case of FRP structures, after an initial concrete crack occurs, FRPs exhibit a rapid shape deformation of the structure after yielding. Thus, in this study we used FRP and PS strand materials and evaluated the ductility index using the load-displacement results obtained from structural tests conducted using various strengthening methods. The ductility index evaluation method compares and analyzes the change rates in the ductility index of PSC and RC structures based on a method that uses structural deflection and the derivation of the energy area ratio. The ductility evaluation results based on the energy area ratio at the crack, yield, and ultimate points showed that all the RC structures, except for the specimens strengthened with reinforcing materials from company H, were in the ductility and semi-ductility sections. Thus, all the PSC structures, except for the control specimens and PH4NP, were found to be brittle.

Simplified and Cost-Effective Method of Studying the Effect of Steel Fibers on Ultra-high Performance Concrete Specimens’ Properties/Members’ Performance

“…The ductility nature of this UHPC beams was also revealed in the slow (and not sudden) increase in the width of the beams' existing cracks after yielding of the tensile steel reinforcements. The ductility reduction of about 48% in the UHPC beam without stirrups can be attributed to the absence of shear reinforcement in the beam; however, it has better ductility when compared with the ductility indices of some studies conducted on high performance concrete and reinforced concrete [45,46,44). Further analysis showed that there was 2.6% difference in the ductility index of the experimental beam with stirrups and the numerically simulated beam with stirrups and steel fibers, while 8.3% difference existed between that of the experimental beam with stirrups and the numerically simulated beam with stirrups but without steel fibers.…”

Comparison of the Bending Behavior of Cylindrically Shaped Lattice Specimens with Radially and Orthogonally Arranged Cells Made of ABS

“…also affects energy dissipation. Roche et al [58] When evaluating the structures' flexural behavior, it was found that both the factors of volume fraction Vf and the type of structure contribute to the results [59], and the combination of these factors makes it impossible to observe any unequivocal regularities in behavior trends in the assessment of ductility. Based on the obtained ductility indices, it can be concluded that the Rhombus structure appears to be the best in terms of ductility; however, the structure showed the lowest values of bending stresses.…”

Researching on the Effect of Input Parameters on the Quality and Manufacturability of 3D-Printed Cellular Samples from Nylon 12 CF in Synergy with Testing Their Behavior in Bending

“…The ductility index, µ E , represents the quotient of the total and elastic energy, and it is expressed by Equation ( 9) [50,51]:…”