Thesis for degree of doctor of science in specialty 05.23.08 – technology and organisation of industrial and civil engineering (19 – Architecture and Construction). – Kyiv National University of Construction and Architecture. – Kyiv, 2021.
In this dissertation number of scientific and theoretical tasks were solved. They are focused on improving of forming efficient system of constructive and technological solutions. This system is based on principles of step by step forming on the basis of identified dependencies of labour intensity, duration and cost of process execution from influence factor during structures restoration by repairing and strengthening. This approach has enabled increase correctness of technology choice at the design stage.
According to analysis results of the issue state of forming Constructive and Technological Solutions (CTS) of the operational state restoration of the structures was identified that demand in restoration works is a mass phenomenon during overhaul, restoration, and also new construction. Current forming systems of CTS do not consider many features of contemporary building materials, machinery, efficient technologies. All these factors caused exploration CTS for the purpose of creating advanced system of their forming and based on study and generalization of factors influence on the justified and rational decision. Involving into system new solutions and developing ones, which use cheaper domestic materials, extend number of suitable solutions.
Theoretical researches of influential factors were carried out, identified range of their confidence interval. Based on results, were identified factors that affect the most on the main processes of building structures restoration. General set of factors was systemized, appropriate groups and subgroups were formed, they mainly identified by: nature and type of damage and defects; amount and type of repair work; processes recurrence; factors of internal and external environment. Evaluation criteria were defined CTS, they include: the degree of restoration of the load-bearing capacity of building structures, complexity, duration and cost of the work. Existing information about first criteria was not enough, that caused carrying out number of experimental researches mainly repairing and strengthening concrete, reinforced concrete and masonry constructions of buildings and structures.
Experimental researches were conducted for linear and slab, horizontal and vertical concrete, reinforced concrete and masonry structures. The technologies of repair of the most common structural damages, namely cracks on the lower surfaces of span structures, the method of their impregnation and repair of damage by adding repair mixtures to the body have been studied. Dependences of increase of bearing capacity of designs on a variant of strengthening which allow to carry out step-by-step selection of ways of performance of processes are established. The efficiency of strengthening span and support constructions by means of plastering external reinforcement, namely plastering high-strength fabrics and lamellas, is provided. External reinforcement provided increasing of bearing capacity up to 4 times for span structures, and up to 2 times for columns. Found out that quality of strengthening of plastering high-strength fabrics and lamellas on the masonry surfaces much depends on surface preparing quality. It is possible to increase bearing capacity of masonry structures up to 6 times by plastering external strengthening.
Based on the received theoretical and experimental data, methods of strengthening building structures were selected and systematized, for which a series of studies were performed to determine the main technical and economic indicators (cost, complexity, duration of work) of selected methods of strengthening each type of structure. Such studies were conducted under normal conditions without the influence of complicating factors. It is identified that specifically for columns the complexity of strengthening processes which provide use carbon fabrics strips is the least. The cheapest way to strengthen is to install a reinforced concrete jacket, and the technology with the installation of carbon fabric strips has the shortest duration (its duration is 12.5 times shorter compared to the installation of a reinforced concrete holder, which is the longest option).
