RESEARCH OF PRECAST CONCRETE FRAGMENTS OF PROTECTIVE SHELTERS
Keywords:
protective shelter, structures, reinforced concrete, emergency impacts, full-scale testsAbstract
This study addresses the construction of modular, quickly assembled reinforced concrete shelters of various classes. The analysis is based on a range of literary, scientific, and technical sources, as well as completed field studies and verification calculations. The author evaluates the advantages and disadvantages of a specific shelter design. The paper includes results from a visual inspection and full-scale testing of a fragment of the protective structure. It provides general information about the design solutions and the outcomes of static tests. The primary goal of the study was to assess the actual technical condition of the shelter and its reliability for its intended purpose. Static calculations established relevant parameters regarding the depth and potential collapse of the shelter to ensure protective properties that align with classes A-I to A-IV. Specific characteristics regarding reinforcement, concrete composition, and wall thickness accompany each respective class. Both visual and instrumental inspections confirmed that the structure met the required geometric dimensions and material specifications outlined in the project and regulatory documents. The test load was calculated at 0.81 of the vertical design load, with no critical damage observed to the shelter ceiling. The study also identified the maximum loads and the primary reasons necessitating design enhancements. Based on the findings from the calculations and full-scale tests, recommendations were developed to improve the reinforcement of prefabricated elements in the protective shelters. Additionally, working drawings were created for the "Varta-3" product, which features enhanced strength against radiation penetration and reduced secondary chipping resulting from blast wave impacts. These improvements were achieved by decreasing the spacing and diameter of the multi-row reinforcement in the shelter's ceiling, thus enhancing the overall concrete structure's performance.
References
Blikharskyi Z. Ya., Karkhut I. I. Calculation and design of bent reinforced concrete elements. Study guide. Lviv, 2017. 188 p.
DBN A.3.1-9-2015. Operational suitability of completed civil protection facilities: Ministry of Communities and Territories Development of Ukraine, Order No 338 of 30.12.2015. Kyiv, 2015. 7 p.
DBN B.1.2-2-2006 with amendments. Loads and impacts. Kyiv: Ministry of Regional Development and Construction of Ukraine, 2006.
DBN B.2.2.5:2023 with amendment 1. Kyiv: Ministry of Development of Communities and Territories of Ukraine Civil Defense Facilities. 131 p.
DBN V.1.2-14-2018. General principles of ensuring the reliability and structural safety of buildings, structures, building structures and foundations. Kyiv, 2018.
DBN V.2.1-10-2018. Bases and foundations of structures. Basic provisions. Kyiv: Ministry of Regional Development and Construction of Ukraine, 2018.
DBN V.2.6-98-2009. Concrete and reinforced concrete structures. Basic provisions. Kyiv: Ministry of Regional Development and Construction of Ukraine, 2009.
DSTU 9208:2022. Heavy concrete. Technical specifications. Kyiv: SE "UkrNDNC", 2022. 24 p.
DSTU B V.1.2-3-2006. Deflections and displacements. Design requirements. Kyiv: Ministry of Regional Development and Construction of Ukraine, 2006.
DSTU B V.2.6-2:2009. Concrete and reinforced concrete products. ZTU. Kyiv: MinregionBud of Ukraine, 2010. 29 p.
DSTU B V.2.7-220:2009. Construction materials. Concretes. Determination of strength by non-destructive testing methods. Kyiv: NDIBK, 2010. 20 p.
DSTU B.2.6-156-2010. Concrete and reinforced concrete structures made of heavy concrete. Kyiv, 2010.
DSTU-N B V.1.2-18-2016. Guidelines for the inspection of buildings and structures to determine and assess their technical condition. Kyiv, 2016.
Instruction on the Maintenance of Civil Defense Protective Structures in Peacetime: Order of the Ministry of Emergencies No 653 of 21.08.2018. Kyiv, 2018. 6 p.
Karkhut I. Improving the crack resistance of inclined cross-sections of reinforced concrete containment shells in areas of emergency loads of pushing. Estern-European Journal of Enterprise Technologies. 2022. Vol. 117, No 4/7. P. 31–41. https://doi.org/10.15587/1729-4061.2022.262337.
Karkhut I. Strength of inclined cross-sections of reinforced concrete protective shells under the action of punching. Theory and Building Practice. Bulletin of NULP. 2022. Vol. 4, No 1. P. 1–17. https://doi.org/10.23939/jtbp2022.01.001.
Rules for Inspection of the Technical Condition of Civil Protection (Civil Defense) Facilities: order of the Ministry of Emergencies No 868/613 of 21.12.2009. Kyiv, 2009. 17 p.
