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Structural Engineering and Mechanics
  Volume 74, Number 3, May10 2020, pages 351-363
DOI: http://dx.doi.org/10.12989/sem.2020.74.3.351
 


Analysis of the dynamic confining effect of CRAC short column under monotonic loadings
Changqing Wang and Jianzhuang Xiao

 
Abstract
    Based on the dynamic tests of recycled aggregate concrete (RAC) short columns confined by the hoop reinforcement, the dynamic failure mechanism and the mechanical parameters related to the constitutive relation of confined recycled aggregate concrete (CRAC) were investigated thoroughly. The fracturing sections were relatively flat and smooth at higher strain rates rather than those at a quasi-static strain rate. With the increasing stirrup volume ratio, the crack mode is transited from splitting crack to slipping crack constrained with large transverse confinement. The compressive peak stress, peak strain, and ultimate strain increase with the increase of stirrup volume ratio, as well as the increasing strain rate. The dynamic confining increase factors of the compressive peak stress, peak strain, and ultimate strain increase by about 33%, 39%, and 103% when the volume ratio of hoop reinforcement is increased from 0 to 2%, but decrease by about 3.7%, 4.2%, and 9.1% when the stirrup spacing is increased from 20mm to 60mm, respectively. This sentence is rephrased as follows: When the stirrup volume ratios are up to 0.675%, and 2%, the contributions of the hoop confinement effect to the dynamic confining increase factors of the compressive peak strain and the compressive peak stress are greater than those of the strain rate effect, respectively. The dynamic confining increase factor (DCIF) models of the compressive peak stress, peak strain, and ultimate strain of CRAC are proposed in the paper. Through the confinement of the hoop reinforcement, the ductility of RAC, which is generally slightly lower than that of NAC, is significantly improved.
 
Key Words
    recycled aggregate concrete (RAC) short column; confined recycled aggregate concrete (CRAC); dynamic confining effect; dynamic confining increase factor (DCIF); compressive peak stress; compressive peak strain; compressive ultimate strain
 
Address
Changqing Wang:
1Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering, China University of Mining & Technology (CUMT), Xuzhou, Jiangsu 221116, China
2Department of Civil Engineering, Shanghai University, Shanghai 200444, China
3Department of Building Engineering, College of Civil Engineering, Tongji University, Shanghai 200092, China
4Jiangsu Collaborative Innovation Center for Building Energy Saving and Construction Technology, Xuzhou, Jiangsu 221116, China
Jianzhuang Xiao: Department of Building Engineering, College of Civil Engineering, Tongji University, Shanghai 200092, China
 

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