Improving the reliability of construction control and quality control of concrete works in the erection of a monolithic building frame

Abstract

The scientific article examines relevant aspects of improving the reliability of construction control and quality control of concrete works during the erection of monolithic frames of multi-storey buildings, where particular importance is attached to minimizing hidden defects arising at various technological stages – from incoming inspection of concrete mixture components to placement, compaction, and curing – since such defects substantially influence the strength, deformation, and durability characteristics of load-bearing structures, thereby determining the overall safety of the facilities under conditions of intensive construction. On the basis of a comprehensive analysis of data obtained during the examination of six residential construction projects ranging from 17 to 32 storeys using concrete classes B25-B40, including the results of testing 1847 control specimens and 2314 non-destructive measurements, a statistical analysis of the distribution of nonconformities is performed. This demonstrates the highest concentration of deviations at the stages of concrete mixture acceptance (23,8 % with a coefficient of variation of strength equal to 0,142) and its placement and compaction (19,4% with a coefficient of 0,118), which correlates with fluctuations in the water-cement ratio, the granulometric composition of aggregates, and violations of the temperature and humidity regime during hardening. A comparative evaluation of methods for determining concrete strength in structures identifies the optimal combination of destructive cube testing (error of 3,4%), pull-out with shearing (5,6%), and non-destructive ultrasonic (8,7%) and impact-pulse (11,2%) approaches; at the same time, integration of these data through Bayesian procedures and wireless temperature monitoring systems allows the total error to be reduced to 2.8-3,8%, simultaneously decreasing the proportion of premature formwork stripping from 8,3 to 0,6% and ensuring the economic payback of implementation within 2,3-2,8 months in the construction of standard complexes. Significant attention is devoted to organizational factors, where expert ranking emphasizes the leading role of inspectors’ qualifications (weight coefficient 0.218), digitalization of documentation (0,187), and independence of control services (0,164), with an established strong inverse correlation (-0,74) between the integral assessment of organizational maturity and the coefficient of variation of strength, indicating the possibility of reducing the latter by 0,011-0,014 with each one-point increase in maturity. The proposed approaches, based on the principles of risk-oriented management, risk matrices, and the integration of control results with building information modeling technologies for the creation of digital twins of structures, ensure optimization of control resource allocation, reduction in overall labor intensity by 18-24% with a simultaneous increase in defect detectability by 12-15%, and the formation of continuous traceability of quality parameters throughout the facility’s life cycle. The presented material enables specialists in concrete technology, construction control, and technical supervision to evaluate the effectiveness of comprehensive improvement of the technical, methodological, and organizational components of the quality management system and to determine the advisability of referring to the full text for implementing the recommendations in corporate standards, regulatory documents, and the practice of erecting monolithic structures.