Enhancement of impact performance of reinforced concrete beams without stirrups by adding steel fibers

Residual behavior of reinforced steel fiber‐reinforced concrete beams damaged by impact

“…The use of SFRC is intended to not only improve the residual load carrying capacity, but more significantly the residual ductility. The research departs from the previous results obtained by Ulzurrun & Zanuy who tested 20 reinforced SFRC beams under drop‐weight impact and companion quasi‐static conditions. Seven SFRC mixtures were studied including three types of steel fibers and two volumetric amounts, in addition to a series of unreinforced plain concrete.…”

“…Quasi‐static tests were carried out by applying a load at midspan with stroke control at a rate of 0.1 mm/s on an undamaged beam of each series. Even though the quasi‐static tests of undamaged specimens have been exhaustively described in, a short summary is included here for the sake of clarity of the present paper. Load‐midspan displacement curves have been plotted in Figure and the crack pattern of beams after quasi‐static testing are represented in Figure .…”

“…Thus, the imparted input energy has been 3.4 kJ. A full description and analysis of impact tests has been reported in . The main results are listed in Table regarding impact strength (considered as the maximum registered total reaction at supports) and absorbed energy (area below the total‐reaction‐midspan deflection diagram), and a brief summary is provided next.…”

“…Because such brittleness can lead to severe human or infrastructure damage, the benefits of adding fibers to the concrete has shown to be an interesting alternative for structures exposed to impacts. Ulzurrun & Zanuy have shown that the use of steel fiber‐reinforced concrete (SFRC) can significantly increase the impact strength of concrete structures due to the higher energy absorption capacity, which can avoid shear‐related failures in SFRC beams containing conventional longitudinal reinforcement and no stirrups (hereafter referred to as reinforced SFRC beams). Other authors have also demonstrated the superior performance against impacts achieved with SFRC.…”

“…An interesting capability of reinforced SFRC elements arises when they do not completely collapse due to the impact, thereby allowing for evacuation of humans and recovery of goods after the impact event. Though existing research has mainly focused on the impact performance of concrete structures, it is also paramount to understand the residual capacity and ductility after impact in order to safely perform evacuation and recovery operations or even evaluate the possibility for rehabilitation.…”