Iranian Sustainable Building Scientific Association International Journal of Urban Management and Energy Sustainability 2538-1628 6 2 2025 04 01 Explaining the effective indexes in the restoration of the natural landscape (Case Study: ancient Iranian historical bridges) 104 123 728224 10.22034/ijumes.2025.2063285.1315 EN Fatemeh Rostami Department of Architecture, CT.C., Islamic Azad University, Tehran, Iran 0000-0002-4693-9131 Ghazal Keramati Department of Architecture, CT.C., Islamic Azad University, Tehran, Iran 0000-0002-1029-2495 Hossein Soltan Zadeh Department of Architecture, CT.C., Islamic Azad University, Tehran, Iran 0000-0002-0239-1397 Journal Article 2025 04 27 Historical buildings, especially architectural structures such as bridges, hold a special place in architecture and the natural landscape, reflecting humanity's ability to combine art and function. Currently, many restoration projects in third-world countries are carried out without adequate attention to natural landscape and architectural indexes, leading to a decrease in the cultural and aesthetic values of the monuments. Meanwhile, throughout history, the architecture of ancient Iranian bridges has played a significant role not only as functional structures but also as cultural and artistic symbols in shaping the natural and cultural landscape of the region. The aim of this study is to examine and develop effective indexes for restoring the natural landscape of ancient Iranian historical bridges. This research is analytical with a practical purpose. The paradigm of the study is interpretive, and the research design is qualitative. Data collection was conducted through library and documentary methods. Initially, content analysis and inductive reasoning were used, followed by a participatory decision-making approach utilizing the fuzzy Delphi model. The findings indicate that conservation of architectural elements, restoration standards, and resilient materials rank highest, with scores of 23.4, 19.4, and 16.4, respectively, in finalizing the model. The conclusion is that the identified indicators should be assessed collectively and simultaneously so that restoration projects can maintain their durability, sustainability, and cultural identity in the long term, and the natural landscape of historic bridges can be properly preserved and restored. Future studies could explore the internal and structural relationships among the indicators. https://www.ijumes.com/article_728224_927b8cd24017eac77a4c979fb2492898.pdf