Retrofitting and improving urban structures with a geotechnical approach

Milad Zakeri Ziyarati¹

1) PhD student in Civil Engineering, Geotechnical Department, Islamic Azad University, North Tehran Branch

Publication : Third International Conference on applied researches in civil engineering, architecture and urban planning (icarcau.com)
Abstract :
Urban structures in earthquake-prone areas such as Iran, Turkey, Pakistan, Italy, and Chile are subject to severe damage due to poor design, poor quality materials, and poor geotechnical conditions. This paper provides a comprehensive review of the methods for retrofitting and improving urban reinforced concrete structures with a focus on the geotechnical approach. The objectives include identifying the causes of damage, evaluating modern soil improvement methods such as jet grouting, base isolation, and shape memory alloys, and combining them with structural retrofitting such as installing shotcrete panels, column jacketing, and retrofitting existing foundations. The research methodology is based on an extensive literature review, analytical modeling in ETABS and OpenSees software, and nonlinear dynamic time history analysis of a 2D concrete frame with a shallow foundation on soft soil. The results show that the installation of shotcrete panels reduces interfacial drift by 50%, and soil improvement with jet grouting and base isolation completely suppresses foundation rotation and differential settlement. This combined approach increases the stability of slab, crawl space, and basement foundations and is suitable for urban structures with individual foundations. Case studies from the Philippines, Tokyo, and Christchurch confirm the effectiveness. Finally, it is suggested that these methods be incorporated into national codes such as Standard 2800 to improve the seismic resilience of cities and prevent widespread destruction in future earthquakes.
Keywords : seismic retrofitting soil improvement jet grouting shotcrete panels foundation isolation soil structure interaction