Articles
Publication Date: 2025
Structures (23520124)81
There are countless valuable historical monuments in Iran, whose restoration and protection are critical. Nevertheless, ignorance of the mechanical behavior of Persian adobes has jeopardized their survival. This research aims to understand the mechanical properties of historical and new Persian adobes through DTS/ITS and modulus of elasticity in tension. To this end, six groups of adobes produced in various time periods were initially collected from historical places in different parts of Iran and adobe production workshops. After preparing specimens from existing adobe materials, several mechanical strength tests, including flexural strength, splitting tensile strength (STS), and DST were conducted according to international standards. The mechanical properties and behavior of the Persian adobes were determined by analyzing the results of the experiments. Load-deflection curves obtained from flexural strength tests and stress–strain curves, stress–strain relations and normalized stress–strain relations obtained from DST test were also presented as another part of the results. Moreover, the relationships between mechanical properties were determined with high accuracy using laboratory data. The results of this research will help engineers and researchers take an effective step toward the international standardization of materials and construction related to adobe and earthen materials through perceiving the mechanical properties and developing knowledge of behavior of Persian adobes. Based on the results, new adobes exhibit higher resistance than their historical counterparts, whose mechanical strengths can be converted to each other with amplification or reduction factors. Therefore, researchers will be able to perform only one type of test to obtain mechanical strengths. Finally, a comparison was drawn between the mechanical properties of Persian adobes and those made in other countries, indicating that adobes around the world possess convergent and similar tensile behaviors. © 2025 Institution of Structural Engineers. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Publication Date: 2025
Soil Dynamics and Earthquake Engineering (02677261)199
This study presents a comprehensive, time-resolved investigation into the effects of localised damage and subsequent restoration on the dynamic behaviour of a semi-circular brick-and-gypsum masonry arch, representative of Persian architectural heritage. Using Operational Modal Analysis (OMA) with Enhanced Frequency Domain Decomposition (EFDD) and Stochastic Subspace Identification (SSI), dynamic responses were evaluated across intact, under three distinct damage scenarios, and following restoration. The findings reveal that both damage location and symmetry significantly influence the arch's dynamic properties. Localised damage led to substantial reductions in natural frequencies, with mode two exhibiting up to 26.6 % reduction in initial damage and 43.5 % in the most severe scenario. Symmetric damage reduced sensitivity in fundamental modes, underscoring the need for multi-modal assessment. Average modal damping ratios increased by up to 107.2 providing more consistent and reliable detection compared to EFDD. Restoration using traditional gypsum mortar significantly improved dynamic characteristics, with natural frequencies recovering by approximately 13.5 % EFDD and 13 % SSI relative to the damaged state. Modal parameters stabilised within 24 h post-restoration; however, certain modes showed incomplete recovery, especially near sensor locations indicating residual stiffness deficits. Damage detection indices of Modal Assurance Criterion (MAC), Normalised Modal Difference (NMD), and Coordinate Modal Assurance Criterion (COMAC) have effectively identified damage, reinforcing their critical role in heritage structural health monitoring. The research highlights the importance of considering restoration as a time-dependent, evolving process, and advocates for integrated and multi-parameter monitoring frameworks. The results offer practical insights for optimising the conservation strategies of historic masonry structures, with recommendations for future work addressing environmental effects, numerical modelling, and advanced restoration materials. © 2025 Elsevier Ltd
