04005nas a2200373 a 4500 20260817161318.0 260130s20249999th u ms t 000 eng d .b12473650 AIT Thesis no.ST-24-10 Rahman, Sajedur A comprehensive evaluation of reinforced concrete structures using strain-based damage index in 3D applied element method Pathum Thani, Thailand : Asian Institute of Technology, 2024 98 leaves : ill.+ 1 online resource Thesis ; no. ST-24-10 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Structural Engineering Thesis (M. Sc.) - Asian Institute of Technology, 2024 Current Finite Element Method (FEM) analysis approaches often underutilize the wealth of data generated and can be computationally expensive. While FEM provides rigorous structural analysis, practical interpretation relies heavily on sectional responses obtained through element meshing, neglecting the full picture of stress and strain distribution at the element level. Existing commercial FEM software also lacks comprehensive visualization capabilities.The 3D Applied Element Method (AEM) addresses these limitations by modeling structures using interconnected elements with springs. Stress and strain outputs are stored at the spring level, facilitating detailed interpretation of element-level structural response. Traditional damage assessment approaches often focus solely on the global structural level, hindering accurate prediction of localized damage behavior under load. This research presents a novel strain-based damage index (DI) implemented within the 3D AEM platform using FORTRAN 95. This DI, based on the second invariant of deviatoric strain, effectively captures damage propagation at the element level. The DI is normalized between 0 and 1 based on material properties, enabling a clear understanding of damage progression from an undamaged state to complete failure. The proposed DI was validated against experimental results and observed cracks in the Filiatrault Frame. The DI closely matched the observed crack propagation pattern, demonstrating its effectiveness. Furthermore, the DI was applied to a case study of an old school building in Dhaka, Bangladesh, highlighting its potential for retrofitting assessments of aging public structures. The building was subjected to ground motions scaled to the Dhaka spectrum with increasing peak ground acceleration (PGA) values (0.42g, 0.54g, and 0.61g). The strain-based DI successfully identified weak zones near the stairs, exceeding safe limits and progressively increasing with higher PGA values (0.016, 0.033, and 0.065 for the three cases). This proposed DI for reinforced concrete structures offers a valuable tool for seismic vulnerability assessment of existing infrastructure. By providing local damage insights, this method can significantly influence local authorities' policymaking regarding safety precautions during major earthquakes. Reinforced concrete Evaluation Concrete construction Evaluation Earthquake resistant design Krishna, Chaitanya, Chairperson Raktipong Sahamitmongkol, Examination Committee Thanakorn Pheeraphan, Examination Committee His Majesty the King{u2019}s Scholarships (Thailand), Scholarship Donor Asian Institute of Technology. Thesis ; no. ST-24-10 Full-Text http://203.159.5.9/ait-thesis/Viewer/viewer.php?id=B23527 .b12473650 mnarc a 260216 0 260211 m h a 0 mnarc 67 Barcode : - CREATED : 2026-01-30 RECORD # : i13570316 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 813 813 0 0 0 0 MAIN MAIN mnarc 2026-08-17 0 AIT Thesis no.ST-24-10 2026-08-17 16:13:18 1 2026-08-17 67