EXPERIENCE IN USING RETAINING WALLS OF EXCAVATIONS AS ENCLOSING STRUCTURES FOR DUAL-PURPOSE UNDERGROUND FACILITIES (SHELTERS) IN MULTI-STOREY BUILDINGS

The study presents data on the damage to multi-storey residential buildings caused by conventional means of destruction, which convincingly demonstrates the necessity of developing and implementing design solutions for shelters located directly in apartments, on floors, or in underground premises of buildings. This research proposes a new design solution for excavation enclosure structures in the form of a retaining wall, which is subsequently integrated into the structural scheme of the building. The proposed approach has been successfully implemented in the construction of new residential buildings in the city of Kyiv. In modern multi-storey residential buildings, underground parking facilities or underground passages – mandatory elements of architectural planning – can be used as dual-purpose structures, alongside the arrangement of "safe rooms" in apartments or on floors. Unlike traditional solutions, this study integrates elements of the retaining wall into the structural system of the building, allowing them to function as structural elements of the dual-purpose structures. Importantly, after the construction of the underground and high-rise sections of the complex, the horizontal loads from the retaining wall will be absorbed by the load-bearing structures of the building. The structural calculations were performed using the Monomakh-CAD 2016 and Lira-CAD 2021 software packages, considering combinations of standard and special loads. The calculations accounted for the reliability factor γn for a class CC3 building and responsibility categories A and B, in accordance with DBN V.1.2-14:2018. The enclosing and load-bearing structures of dual-purpose facilities are designed to withstand combinations of loads under both normal and emergency conditions. The primary load combinations are determined according to the requirements of "DBN V.1.2-2". According to "DBN V.2.2-5:2023", quasi-static loads from air shock waves were added to the emergency load combinations for shelter group P-1. The study presents a structural solution for integrating excavation retaining walls into the structural framework of the underground floors of multi-storey residential buildings. Structural nodes for connecting elements of the excavation retaining wall to the load-bearing structures of underground floors have been developed. The feasibility of using excavation retaining walls integrated into the building's structural system as dual-purpose structures with protective properties, meeting the requirements for radiation-proof shelters of group P-1 under "DBN V.2.2-5:2023", has been substantiated.