Experimental Investigation of the Effect of Steel Fibers on the Flexural Behavior of Corroded Prestressed Reinforced Concrete Beams

Rebar corrosion and its consequences are one of the most common damages to reinforced concrete (RC) structures. In structures with greater sensitivity, such as prestressed reinforced concrete (PRC) structures, where steel elements, including prestressed tendons, play a more significant role in supporting the structure, the importance of this issue increases. Methods for repairing and reinforcing such structures have been developed, including incorporating fibers into the concrete mixture to improve its mechanical properties, particularly its bending resistance. This paper presents the results of an experiment that studied the influence of steel fibers on the flexural behavior of PRC beams subjected to accelerated corrosion. Twelve beams with a rectangular cross-section of 150 mm × 300 mm and a length of 2000 mm were fabricated. The steel fibers used in the experiment were corrugated and hooked-end types, with volume fractions of 0.5% and 1.0% in the concrete. Nine beams were subjected to accelerated corrosion testing, with three of them being without fibers and the remaining six being reinforced with steel fibers at volume fractions of 0.5% and 1.0%. Each group of three beams was exposed to three different levels of corrosion, namely 5%, 10%, and 15%. The specimens were tested after exposure to corrosion through a four-point bending load. The accelerated corrosion was induced using an electric current on the prestressing tendons. The results indicated that different levels of corrosion reduced the final bearing capacity and other behavioral characteristics of the specimen, including the amount of energy absorption, effective hardness, and midspan displacement. Adding fibers to the concrete mixture positively affects the compensation of these reduced capacities. Moreover, the amount of this compensation was directly correlated with the volume fraction of used fibers

Assesment Behaviour of the concrete flexural frame and shear wall Partially Buried system under Blast Loadings

Nowaday, with the proliferation of terrorist attacks on buildings in the world, a close examination of the behavior of structures under blast loads is a necessity. Pressure caused by the explosion of one of the most destructive loads that the structure may experience. Since the existing structures are usually designed to the common gravity and seismic loads, it is necessary to investigate their performances under blast loadings. In this study, analytical studies have been done for 2D structural models of concrete flexural frame and shear wall Partially Buried system with different number of stories 2 and 5. structures assessed based on the UFC 3-340-02 guidelines for 1000 kg TNT blast from 20 meters, the software SAP 2000 Design and nonlinear dynamic analysis have been. In order to loading, pressure values obtained from the explosion's blast wave, shock waves and pressure from the calculated reflection and As well as air blast wave parameters, including speed wavefront, period and wavelength explosion was determined and pressure graph - time of the explosion is offered. After analysis, The plastic hinge rotation, the formability and the highest axial force, shear force and bending moment occurred members, as well as maximum displacement, velocity and acceleration absolute floor level roof for all models will be investigated