State-of-the-art review on low-velocity impact response of reinforced concrete beams

Abstract

Based on a comprehensive literature review, a state-of-the-art report on the strain rate dependent mechanical properties of materials involved in reinforced concrete (RC) structures and the structural response of RC beams under low-velocity impact is presented. Due to the prevalence of plentiful equations to calculate the dynamic increase factor of concrete strength in compression and tension, future research is needed to reach a general consensus. Two empirical equations were derived based on previous test data, and the applicability of the proposed equations is demonstrated. With the interpretation of previous data in the light of authors' test results, the issue related to a change in failure mode from flexural failure under static loading to shear failure under impact loading is discussed. Finally, several issues related to the impact response of beams are raised, and the need for future research is identified.

The Theory of Critical Distances to assess failure strength of notched plain concrete under static and dynamic loading

“…Table 1 summarises the most popular approaches that, since about the middle of the last century, have been devised (and somehow validated) to estimate dynamic strength of concrete [22,23]. The governing equations reported in Table 1 are in the form of logarithmic polynomials that fit the experimental data, with strain rate ε & being the independent variable.…”

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

“…It seems that when the impact causes a shear plug, the critical section is forced at midspan region, which can be more ductile than a shear‐critical undamaged beam. Change of failure mode from brittle for undamaged specimens to ductile for impact‐damaged specimens can be also observed from the experiments of reinforced concrete beams of (series SR3.8‐0.8) but no specific analysis was carried on.…”

“…The decrease in strength of impact‐damaged specimens with respect to undamaged beams can be expressed with the RRI index proposed by Adhikary et al, which is listed in Table . According to RRI obtained, the degree of damage caused by the impact can be classified as low (RRI > 0.8) in general, with even no damage for the beam of series F, and some higher damage for one beam of series E (medium according to for 0.6 < RRI < 0.8). However, it is clear that RRI values do not inform about the residual failure mode or the residual energy absorption capacity.…”

“…Only few researchers have studied the residual capacity of concrete structures damaged by dynamic actions. Adhikary et al performed quasi‐static tests on reinforced concrete beams previously subjected to drop‐weight impacts. They proposed two indices (RRI: residual resistance index, RSI: residual stiffness index) to define the impact damage and they concluded a beneficial effect of high amount of transverse reinforcement, low longitudinal reinforcement ratio, and high concrete compressive strength.…”

Flexural Reinforced Concrete Members With Minimum Reinforcement Under Low-Velocity Impact Load

“…Adhikary [12,13] comprehensively reviewed and collected the past experimental results about the test of low-velocity impact response of RC beams. The relationship between the maximum midspan deflection and the input impact energy over static resistance (both flexural and shear resistance) was proposed for impact-resistance design.…”