Jae-Yeol Cho

In this paper, the compressive behavior of fiber-reinforced concrete with end-hooked steel fibers has been investigated through a uniaxial compression test in which the variables were concrete compressive strength, fiber volumetric ratio, and fiber aspect ratio (length to diameter). In order to minimize the effect of specimen size on fiber distribution, 48 cylinder specimens 150 mm in diameter and 300 mm in height were prepared and then subjected to uniaxial compression. From the test results, i

The dynamic increase factor (DIF) has been widely used to consider the rate effect in the analysis and design of concrete structures that are subject to impact loads. A variety of DIFs have been proposed by many researchers based on the results of dynamic material tests such as the split Hopkinson pressure bar (SHPB) test. These DIFs have been adopted in authoritative design guidelines and model codes such as the ACI 349–13, ACI 370R-14, fib MC2010, and UFC 3-340-02. However, previous studies di

This study includes the experimental and numerical research conducted to establish a standardized lubrication technique for a concrete split Hopkinson pressure bar (SHPB) test. Concrete SHPB tests were conducted using different quantities of high-vacuum grease, petroleum jelly, and Teflon to determine a desirable lubrication method. Subsequently, follow-up concrete SHPB tests with different specimen dimensions were performed to validate the proposed lubrication method and obtain a dynamic increa

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Dynamic increase factor (DIF) has been used to consider rate effect on compressive strength of concrete in both design and analysis of concrete structures loaded with high rate. Until now, a variety of DIFs have been suggested by various researchers, and these DIFs are adopted in design guidelines and model codes, e.g., ACI 349-13, ACI 370R-14, fib MC2010, and UFC 3-340-02. However, the DIFs includes the axial and radial inertia effects, which cause confining effect and resistance to deformation

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With the advancement of material science and infrastructure design technology, there is an increased need to reflect various loading scenarios in the design of civil infrastructures, including extreme loads such as impact and blast. However, structural behavior under extreme loads has been observed to be very different from that under static loads due to the high-rate loading condition. Therefore, extensive experimental and analytical studies have been conducted to explain the structural behavio

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Recently, the demand of the structural safety subjected to impact loading has been increased. For this reason, various studies for predicting the behavior of structures under impact loading have been actively performed. Some researchers have suggested performance based design to predict the behaviors of structures. They conducted drop weight impact test and suggested empirical equations to estimate the maximum or residual deflection of reinforcement concrete (RC) beams under impact loading based