PSI - Issue 64

Maysam Jalilkhani et al. / Procedia Structural Integrity 64 (2024) 161–167 Author name / Structural Integrity Procedia 00 (2019) 000–000

166

6

Assessing a building’s capacity to withstand the seismic lateral forces involves evaluating key parameters, notably the design story drift ( Δ ). This drift is computed as the difference in deflections at the centers of mass, comparing the top and bottom of the story under consideration. These structural deformations can negatively affect both the structural and non-structural elements of buildings, potentially impacting adjacent structures. The lateral story drift can be observed during seismic events and may result in reversible or irreversible damage depending on event characteristics and building attributes. Guidelines typically stipulate limit values for drift, primarily concerning lateral movement induced by lateral forces such as earthquakes. The regulation regarding drift is usually expressed as a fraction or percentage of the story height, contingent upon the structural system type and non-structural systems involved. For example, Eurocode 8 (2004) stipulates drift limits ranging from 0.005 h to 0.010 h (where h is the story height), depending on factors such as the presence of brittle non-structural materials, ductile non-structural elements, or the absence of fixed non-structural elements. Moreover, these prescribed values need to be modified using the reduction factor, which accounts for the seismic action’s lower return period associated with damage limitation requirements. 6. Proposed methodology Based on the information presented above, this paper proposes a three-tiered framework for assessing mining induced damage in buildings: 6.1. First level: Initial Assessment The paper presents a rapid categorization approach for assessing expected building damage at a city-wide scale, utilizing both empirical and analytical models discussed earlier. Previous research, as outlined in Section 2, highlights the correlation between damage and factors such as building length and horizontal ground strain induced by mining activities. However, these methods predominantly rely on empirical development and need validation under different conditions. Therefore, the proposed methodology will require validating existing approaches through qualitative assessments conducted during surveys of buildings near the mine. This validation will enable rapid screening of expected damage under diverse scenarios of ground movement, subsidence, or ground motions. Subsequently, based on the results of this first level assessment, a more detailed analysis of the damage evolution in identified vulnerable buildings will be performed at Level 2. 6.2. Second level: Moderate Assessment In Level 1 building assessment, additional characteristics beyond those initially considered are necessary to analyze damages thoroughly. These include structural drawings and comprehensive surveys detailing any existing damage. The assessment criteria encompass: (1) Foundation type (rigid, flexible), (2) Structural systems (such as frames, walls, and masonry), (3) Material properties (brittle or flexible), (4) Presence of stiffeners (e.g., elevator, shear walls), (5) Building geometry aspect ratio (tall or short), and (6) Visible damage. Furthermore, quantitative measurements of damage parameters (such as crack dimensions, drift, and settlements) will be performed and compared against established guidelines and assessment methodologies. This approach enables a qualitative assessment of building damage and improves understanding of their expected future behavior. 6.3. Third level: Detailed Assessment At this level, a comprehensive structural damage assessment will be conducted. This includes the development of finite element models (FEMs) for specific buildings, calibrated using data from crack monitoring and ground subsidence measurements. FEM simulations will be iteratively updated with monitoring data to evaluate different risk scenarios under different subsidence and seismicity scenarios. Findings from levels 1 and 2 will inform the selection of buildings eligible for the third-tier assessment.