Experimental and numerical investigations on the size effect of moderate high-strength reinforced concrete columns under small-eccentric compression

Abstract

The paper deals with an experimental investigation and numerical simulation of moderate high-strength reinforced concrete (RC) columns subjected to a small-eccentric compressive loading ( e0 = 0.25 h0). A series of tests on the behavior of 12 geometrically similar moderate high-strength reinforced concrete columns with two different stirrups ratios (i.e., 0% and 0.66%) were conducted. The maximum structural size of the square reinforced concrete columns was 800 mm. A 2D mesoscale method for the simulation of the behavior of reinforced concrete columns was established. The numerical tests on the reinforced concrete columns with larger stirrup ratios (1.2% and 2.4%) were carried out complementarily, based on the fact that the simulation results were consistent with the available test observations. The failure patterns, the nominal compressive stress–strain relationships, the nominal compressive strength, and the post-peak softening behavior of the reinforced concrete columns were studied. Furthermore, the influence of stirrups on failure behavior and size effect of the reinforced concrete columns was revealed. One can conclude that (1) the size effect exists in the nominal compressive strength of the eccentrically loaded high-strength reinforced concrete columns with the four different stirrup ratios; (2) comparison of the present test results and the “size effect law” proposed by Bažant shows good agreement; (3) the presence of stirrups improves the nominal strengths, makes the failure of columns less brittle, and weakens the size effect; and (4) the proposed mesoscale numerical method is capable of describing the mechanical behavior of eccentrically loaded reinforced concrete columns.

A combined experimental and numerical analysis on the seismic behavior of short reinforced concrete columns with different structural sizes and axial compression ratios

“…The specimen was loaded with both axial compression and horizontal loading with a shear-span ratio of 2.58; the failure was consequently not controlled by shear but moment. Therefore, the specimen presented a failure pattern similar with an eccentrically loaded RC column (Jin et al., 2016c, 2017; Majewski et al., 2008; Xu et al., 2016). CC-5-0.6, CC-7-0.4, and CC-7-0.6 were all under cyclic horizontal loads at the base of the specimen, and they exhibited similar failure patterns with large damage area at bottom region of the column.…”

“…For more details about the constitutive model, refer to the work of Huang et al. (2016) and Jin et al. (2017).…”

“…To avoid or relax unreasonable mesh sensitive results, the tensile postfailure behavior is given in terms of a fracture energy cracking criterion by specifying a stress–displacement curve instead of a stress–strain curve, e.g. in the efforts (Du et al., 2013; Genikomsou and Polak, 2015; Huang et al., 2016; Jin et al., 2017). Nevertheless, it is to be noted that the use of a fracture energy approach provides mesh-independent results for load–displacement diagrams only.…”

Modeling the hysteretic responses of RC shear walls under cyclic loading by an energy-based plastic-damage model for concrete

“…Similar work includes Feng et al (2018) and Palermo and Trombetti (2016). Note that damage mechanics have also been widely applied to the modeling of concrete materials under static (Chen et al, 2018;Jin et al, 2018a;Li and Wu, 2018;Suchorzewski et al, 2018;Vorobiev et al, 2018), fatigue (Ding and Li, 2018), and dynamic (Hu et al, 2018;Jin et al, 2018bJin et al, , 2018cYang et al, 2019) loadings as well as harsh environments (Dong et al, 2018;Luo et al, 2018). The remainder of the paper is structured as follows.…”

Localization of deformation and its effects on power-law singularity preceding catastrophic rupture in rocks

“…Localization of deformation and damage is a general phenomenon in concrete (Jin et al, 2018;Li and Wu, 2018;Markeset and Hillerborg, 1995) and geological materials (Baud et al, 2004;Dewers et al, 2017;Harnett et al, 2018;Xu et al, 2004) and serves as an effective precursor of catastrophic rupture (Hao et al, 2007(Hao et al, , 2010Li et al, 2000). After localization, the strain field of a specimen bifurcates into a two-part continuum consisting of a less-deformation zone and a localized band where the deformation and damage are concentrated (Bai et al, 2001;Colpo et al, 2017;Hao et al, 2007Hao et al, , 2010Hill and Hutchinson, 1975;Lockner et al, 1991;Rudnicki and Rice, 1975;Toussaint and Pride, 2002).…”