Nonlinear dynamic behaviour of severely corroded reinforced concrete columns: shaking table study

Abstract

A set of benchmark, medium scale, shaking table tests on corroded reinforced concrete (RC) columns is conducted with the aim of investigating the effects of corrosion damage on the nonlinear dynamic behaviour of RC bridge piers. The experimental programme consists of an uncorroded control specimen and two corroded RC column specimens, with identical structural details. An accelerated corrosion procedure is used to corrode the RC columns. The uncorroded and corroded specimens are subjected to far-field long duration ground motion excitations. The two corroded columns had 51% and 65% average mass loss ratios. The testing sequence includes slight, extensive, and complete damage levels, followed by an aftershock to examine the cascade effect on the nonlinear dynamic response of the proposed RC columns. The experimental results show that corrosion changes the failure mode of the RC columns, and has a significant negative impact on the residual strength (about 50% mass loss results in about 80% strength reduction) and drift capacity of RC columns.

Rapid post-earthquake damage assessment of ageing reinforced concrete bridge piers using time-frequency analysis

“…In this section, only a summary of the experimental results is provided. The detailed discussion of experimental results and structural damage are beyond the scope of this paper and are reported in different publications (Ge et al, 2019;Kashani, Ge, et al, 2019). The FF-LC-Corr1 specimen failed after 10s in the extensive (300%) damage level test.…”

“…In order to investigate the seismic behaviour of uncorroded and corroded RC bridge piers in terms of the effects of ground motion characteristics, structural detailing and corrosion levels, a series of shaking table tests are conducted on six large-scale RC columns. The experimental campaign is included four uncorroded and two corroded columns (Ge et al, 2019;Kashani, Ge, et al, 2019). The columns with cross-sections of 250mm×250mm are cast in a 1500mm × 700mm × 300mm foundation.…”

“…The experiment illustrates that (i) the ground-motion type and duration affect the peak displacement response owing to the excitation amplitude; (ii) the stiffness degradation of the RC column is mainly caused by concrete cover spalling and core crushing in well confined columns, and this factor is aggravated by inelastic buckling of the vertical reinforcement in lightly confined columns; (iii) compared with uncorroded RC columns, the corroded ones exhibit larger displacement response, smaller ultimate strength and less energy dissipation capacity due to corrosioninduced concrete cracking and steel bar fracture. The detailed discussion of the experimental findings can be found in the authors' previous works (Ge et al, 2019;Kashani, Ge, et al, 2019).…”

“…The frequency estimate of FF-LC-Corr2 specimen in the 300% test also shows less good agreement. The rocking movement of this specimen was observed during the experiment (Ge et al, 2019), as the vertical bars were fractured. Therefore, the acceleration response is very small even though the excitation amplitude is large (see Figure 14(e)).…”

Implementation of a Novel Inertial Mass System and Comparison to Existing Mass-Rig Systems for Shake Table Experiments

“…Several shake table experiments on cantilever RC columns have been performed by positioning the inertial mass directly on top of the specimen's head and subjecting it to the earthquake ground motion record. Examples of such studies can be found in the works by Mosalam et al [12], Sakai et al [13], Schoettler et al [6], and Ge et al [14]. In this configuration, the axial force on the column model generated by the superstructure weight and the P-Δ effect can be replicated.…”