Damage Analysis of Reinforced Concrete Structures with Substandard Detailing

Abstract

This is the unspecified version of the paper.This version of the publication may differ from the final published version. Abstract The goal of this study is to investigate seismic behaviour of existing R/C buildings designed and constructed in accordance with standards that do not meet current seismic code requirements. In these structures, not only flexure, but also shear and bond-slip deformation mechanisms need to be considered, both separately and in combination. To serve this goal, a finite element model is developed for inelastic seismic analysis of complete planar R/C frames. The proposed finite element is able to capture gradual spread of inelastic flexural and shear deformations as well as their interaction in the end regions of R/C members. Additionally, it is capable of predicting shear failures caused by degradation of shear strength in the plastic hinges of R/C elements, as well as pullout failures caused by inadequate anchorage of the reinforcement in the joint regions. The finite element is fully implemented in the general inelastic finite element code IDARC2D and it is verified against experimental results involving individual column and plane frame specimens with non-ductile detailing. It is shown that, in all cases, satisfactory correlation is established between the model predictions and the experimental evidence. Finally, parametric studies are conducted to illustrate the significance of each deformation mechanism on the seismic response of the specimens under investigation. It is concluded, that all deformation mechanisms, as well as their interaction, should be taken into consideration in order to predict reliably seismic damage of R/C structures with substandard detailing. Permanent repository link

A combined local damage index for seismic assessment of existing RC structures

“…The finite element model [6][7][8] adopted herein for seismic damage analysis of existing RC structures is based on the flexibility approach (force-based element) and belongs to the class of phenomenological models. It consists of three sub-elements representing flexural, shear, and anchorage slip response (Fig.…”

“…The M-φ hysteretic model is composed by the skeleton curve and a set of rules determining response during loading, unloading, and reloading. The M-φ envelope curve is derived by section analysis and appropriate bilinearization [8] with corner points corresponding, as a rule, to yielding and failure. Curvature capacity φ u is considered as the minimum value from those corresponding to hoop fracture due to strain arising from the expansion of the concrete core [16], buckling of the longitudinal reinforcement [17], strength degradation exceeding 20% of the maximum moment capacity, and fracture of the tension reinforcement in the tension zone.…”

“…Loading response is assumed to follow the bilinear envelope curve. Unloading is characterized by mild stiffness degradation; this is achieved by setting the unloading parameter of the Sivaselvan and Reinhorn [18] Reloading aims at the point with previous maximum excursion in the opposite direction [6,8].…”

“…The yield penetration coefficients specify the proportion of the element where the acting moment is greater than the end-section yield moment. These coefficients are first calculated for the current moment distribution and then compared with the previous maximum penetration lengths [6,8].…”

“…The authors [5][6][7][8] have developed a finite element capable of reproducing all three inelastic deformation mechanisms in an F o r P e e r R e v i e w 2 explicit manner. This model is able to follow gradual spread of inelastic flexural and shear deformations as well as their interaction in the end regions of RC members.…”