Evaluation of Damage Limit State for RC Frame Based on FE Modeling

Abstract

Many damage limit states have been defined to characterize the extent of damages occurred in RC frame. Some of the damage limit states are defined by models that relate the limit states with the control points. Both control points and the limit state are expressed in term of response quantities. This research aims to evaluate the validity of such models by identifying the defined damage limit state with the corresponding damage based on FE modeling. The FE modeling provides a direct link between the damage and the response quantities. This link can be exploited as a basis for the evaluation. Based on the evaluation, this study proposed modified damage limit states. The response quantities with its corresponding progressive damage from FE simulation will also be used to inspect whether damage that can be expected to occur in the model structure is within the range estimated by the code based approach (CBA) damage limit state. Finally, fragility curves are constructed to assess the probability of the expected damage in the model structure under Design Basis Earthquake (DBE) and Maximum Considered Earthquake (MCE) scenarios. Utilizing the proposed damage limit states, the most probable damage in the structure falls in the category of slight if an earthquake at a level of DBE or MCE strikes the structure. However, at MCE level the probability of moderate damage attains 35%, or an increase by 23% compared to the DBE level.

Time‐dependent seismic fragility curves for existing RC core‐wall buildings exposed to corrosion

“…For RC framed buildings, the extent of damage is usually controlled by the Inter-Story drift Ratio (IDR), and quite consolidated drift threshold values associated with EMS-98 damage grades 43 can be found in the technical literature. 44 This type of approach is also followed in Hazus-MH 2.1 Technical Manual, 45 which refers to different building typologies, three different height categories (low, mid, and high rise), and four design levels. However, the use of IDR may be inappropriate in the case of RC core-walls, as discussed in.…”

“…11 On the other hand, FE analyses allow a detailed representation of damage phenomena (cracking, crushing, yielding, and buckling) and their evolution as loading increases. 44 Therefore, damage thresholds can be more precisely identified with reference to material strain limits, similarly to the approach firstly introduced by Crowley and others. 46 Damage thresholds' identification based on material-based EDPs for irregular existing RC buildings with shear walls has been already proposed by some of the authors in, 11 according to Table 3 (see raw named "Material-based EDPs").…”

“…The definition of damage thresholds for fragility assessment is strictly related to the identification of suitable structural response quantities, known as engineering demand parameters (EDPs). For RC framed buildings, the extent of damage is usually controlled by the Inter‐Story drift Ratio (IDR), and quite consolidated drift threshold values associated with EMS‐98 damage grades 43 can be found in the technical literature 44 . This type of approach is also followed in Hazus‐MH 2.1 Technical Manual, 45 which refers to different building typologies, three different height categories (low, mid, and high rise), and four design levels.…”

“…However, the use of IDR may be inappropriate in the case of RC core‐walls, as discussed in 11 . On the other hand, FE analyses allow a detailed representation of damage phenomena (cracking, crushing, yielding, and buckling) and their evolution as loading increases 44 . Therefore, damage thresholds can be more precisely identified with reference to material strain limits, similarly to the approach firstly introduced by Crowley and others 46 .…”

Seismic Behavior of Existing Reinforced Concrete Columns with Non-Seismic Details under Low Axial Loads

“…Many studies have been conducted to upgrade the seismic performance of existing RC buildings [ 7 , 8 , 9 ]. Analytical models for RC elements have been developed to improve the accuracy of seismic evaluation [ 10 ], and theoretical and numerical approaches for damage modeling of concrete structureshave also been discussed [ 11 , 12 , 13 ]. Nevertheless, on-site implementation is difficult to achieve, and operations may not be properly conducted if the construction supervisor does not perform sufficient checks, resulting in issues such as poor quality of the 135° hooks in the transverse shear reinforcement and inconsistent spacing between transverse reinforcement even in recent years [ 14 ].…”