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Cyclic bond behavior in reinforced concrete flexural members exposed to elevated temperatures
https://orcid.org/0000-0001-5454-6584
Highlights 26 modified beam-end specimens were fabricated, exposed to heat, and tested. Different diameters of rebar, concrete strengths, confinement levels, and exposure temperatures studied. Changes in monotonic and cyclic bond-slip behavior due to exposure to elevated temperatures discussed. Recommendations are made for estimating the backbone load-slip curves for RC members exposed to elevated temperatures.
Abstract After enduring fire incidents, many reinforced concrete (RC) structures require assessment of their ability to withstand future seismic loads. A critical factor contributing to seismic behavior of such structures is residual bond between steel and concrete under cyclic loading. This paper examines cyclic bond-slip behavior in RC flexural members that have experienced elevated temperatures. Twenty-six modified beam-end specimens with different diameters of longitudinal reinforcement, concrete strengths, and confinement levels were fabricated. The specimens were subjected to a variety of heating regimes and a natural cool down before loading of their longitudinal rebar in a monotonic or cyclic pattern. The decrease in bond strength after 2-hr exposure to temperatures of 400, 600, and 700 °C were 23, 58, and 65 percent for monotonic loading but 30, 60, and 65 percent for cyclic loading, respectively. Elevated temperatures also caused a decrease in slope and area of hysteretic bond-slip loops. Cyclic bond strength was 25–45% less than monotonic bond strength and better correlated with the residual compressive strength of concrete, unlike monotonic bond strength, which was better correlated with the square root of this property. A model was proposed for backbone bond-slip curves of RC flexural members that are exposed to elevated temperatures.
Cyclic bond behavior in reinforced concrete flexural members exposed to elevated temperatures
https://orcid.org/0000-0001-5454-6584
Highlights 26 modified beam-end specimens were fabricated, exposed to heat, and tested. Different diameters of rebar, concrete strengths, confinement levels, and exposure temperatures studied. Changes in monotonic and cyclic bond-slip behavior due to exposure to elevated temperatures discussed. Recommendations are made for estimating the backbone load-slip curves for RC members exposed to elevated temperatures.
Abstract After enduring fire incidents, many reinforced concrete (RC) structures require assessment of their ability to withstand future seismic loads. A critical factor contributing to seismic behavior of such structures is residual bond between steel and concrete under cyclic loading. This paper examines cyclic bond-slip behavior in RC flexural members that have experienced elevated temperatures. Twenty-six modified beam-end specimens with different diameters of longitudinal reinforcement, concrete strengths, and confinement levels were fabricated. The specimens were subjected to a variety of heating regimes and a natural cool down before loading of their longitudinal rebar in a monotonic or cyclic pattern. The decrease in bond strength after 2-hr exposure to temperatures of 400, 600, and 700 °C were 23, 58, and 65 percent for monotonic loading but 30, 60, and 65 percent for cyclic loading, respectively. Elevated temperatures also caused a decrease in slope and area of hysteretic bond-slip loops. Cyclic bond strength was 25–45% less than monotonic bond strength and better correlated with the residual compressive strength of concrete, unlike monotonic bond strength, which was better correlated with the square root of this property. A model was proposed for backbone bond-slip curves of RC flexural members that are exposed to elevated temperatures.
Cyclic bond behavior in reinforced concrete flexural members exposed to elevated temperatures
https://orcid.org/0000-0001-5454-6584
Highlights 26 modified beam-end specimens were fabricated, exposed to heat, and tested. Different diameters of rebar, concrete strengths, confinement levels, and exposure temperatures studied. Changes in monotonic and cyclic bond-slip behavior due to exposure to elevated temperatures discussed. Recommendations are made for estimating the backbone load-slip curves for RC members exposed to elevated temperatures.
Abstract After enduring fire incidents, many reinforced concrete (RC) structures require assessment of their ability to withstand future seismic loads. A critical factor contributing to seismic behavior of such structures is residual bond between steel and concrete under cyclic loading. This paper examines cyclic bond-slip behavior in RC flexural members that have experienced elevated temperatures. Twenty-six modified beam-end specimens with different diameters of longitudinal reinforcement, concrete strengths, and confinement levels were fabricated. The specimens were subjected to a variety of heating regimes and a natural cool down before loading of their longitudinal rebar in a monotonic or cyclic pattern. The decrease in bond strength after 2-hr exposure to temperatures of 400, 600, and 700 °C were 23, 58, and 65 percent for monotonic loading but 30, 60, and 65 percent for cyclic loading, respectively. Elevated temperatures also caused a decrease in slope and area of hysteretic bond-slip loops. Cyclic bond strength was 25–45% less than monotonic bond strength and better correlated with the residual compressive strength of concrete, unlike monotonic bond strength, which was better correlated with the square root of this property. A model was proposed for backbone bond-slip curves of RC flexural members that are exposed to elevated temperatures.
Cyclic bond behavior in reinforced concrete flexural members exposed to elevated temperatures
Asghari Ghajari, Farjam (author) / Yousefpour, Hossein (author)
Engineering Structures ; 292
2023-06-20
Article (Journal)
Electronic Resource
English
Cyclic Behavior of Reinforced Concrete Flexural Members Using High-Strength Flexural Reinforcement
| Online Contents | 2014