A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Effect of Sustained Load Level on Long-Term Deflections in GFRP and Steel-Reinforced Concrete Beams
Abstract ACI 440.1R [1] applies an adjustment factor of 0.6 to the long-term deflection multiplier for steel-reinforced beams to reflect the experimentally observed differences between FRP and steel-reinforced members. The objective of this study is to evaluate the effect of the level of sustained load on the long-term multiplier in GFRP-reinforced beams. Five beams, including four GFRP-reinforced beams and one steel-reinforced control beam, were tested in four-point bending on a simply supported span with different temporary service loads (M a = 1.80 M cr–2.36 M cr) and sustained load (M sus = 0.58 M a–0.85 M a) levels. Mid-span deflections were recorded twice weekly over a period of 100 days, and the long-term deflection multiplier, λΔ, was plotted vs. time. The results indicate that the temporary service load level, rather than the sustained load level, affects the long-term deflection multiplier with larger temporary service loads causing a smaller long-term multiplier. The current 0.6 multiplier on the time factor for FRP-reinforced beams also appears to underestimate long-term deflections. In addition, the multiplier to capture the effects of GFRP vs. steel-reinforcement may not be a constant value.
Effect of Sustained Load Level on Long-Term Deflections in GFRP and Steel-Reinforced Concrete Beams
Abstract ACI 440.1R [1] applies an adjustment factor of 0.6 to the long-term deflection multiplier for steel-reinforced beams to reflect the experimentally observed differences between FRP and steel-reinforced members. The objective of this study is to evaluate the effect of the level of sustained load on the long-term multiplier in GFRP-reinforced beams. Five beams, including four GFRP-reinforced beams and one steel-reinforced control beam, were tested in four-point bending on a simply supported span with different temporary service loads (M a = 1.80 M cr–2.36 M cr) and sustained load (M sus = 0.58 M a–0.85 M a) levels. Mid-span deflections were recorded twice weekly over a period of 100 days, and the long-term deflection multiplier, λΔ, was plotted vs. time. The results indicate that the temporary service load level, rather than the sustained load level, affects the long-term deflection multiplier with larger temporary service loads causing a smaller long-term multiplier. The current 0.6 multiplier on the time factor for FRP-reinforced beams also appears to underestimate long-term deflections. In addition, the multiplier to capture the effects of GFRP vs. steel-reinforcement may not be a constant value.
Effect of Sustained Load Level on Long-Term Deflections in GFRP and Steel-Reinforced Concrete Beams
Walkup, Stephanie L. (author) / Musselman, Eric S. (author) / Gross, Shawn P. (author)
2018-01-01
7 pages
Article/Chapter (Book)
Electronic Resource
English
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