METHODS OF ESTIMATION OF THE SHEAR STRENGTH OF THE CONTACT JOINTS OF CONCRETE LAYERS

Visnyk LNAU: Architecture and Farm Building 2020 №21: 21-26

METHODS OF ESTIMATION OF THE SHEAR STRENGTH OF THE CONTACT JOINTS OF CONCRETE LAYERS

Mazurak A., Candidate of Engineering Science
Lviv National Agrarian University
Kalchenko V., Post-graduate Student
Lviv National Agrarian University
Tsap O., Post-graduate Student
Lviv National Agrarian University
Mikhailechko V., Senior teacher
Lviv National Agrarian University
Sobchak-Piаstka Ju. Candidate of Engineering Science
University of Technology and Life Sciences in Bydgoszcz

https://doi.org/10.31734/architecture2020.21.021

Annotation

In the modern construction, there is often a need to restore, repair, reinforce concrete and reinforced concrete structures. In its turn, it requires a strong connection of different layers of concrete.

The problem of shear resistance of contact joints of concrete and reinforced concrete structures has been investigated by many scientists, but today a reliable and physically sound method of calculating the strength of contact joints for the action of shear forces has not been proposed. Concurrent work of concrete of the existing matrix structure and new concrete or reinforced concrete, as shown by the practice of use and already conducted experimental researches, is the basic criterion of bearing capacity for reinforcement, repair of concrete and reinforced concrete structures.

After conducting the analytical review of the literature, based on the experience of predecessors and known methods of strength assessment, experimental studies of the characteristics of the cut strength of contact seams are proposed at reinforcement of concrete and reinforced concrete elements.

To make experimental studies, the researchers used concrete samples "G" of the similar shape with a cross section of 100x100mm and a height of 400 mm. The samples were interconnected with different combinations: unreinforced contact area, also using adhesive coatings to increase adhesion; tilting connection; the combination of elements with different characteristics of concrete. The prepared specimens were kept for 60 days, after proper preparation, the specimens were loaded vertically to ensure a clean cut.

The studies have made it possible to evaluate the impact on the strength of the cut joints of contact seams: concrete class, the presence of connecting substrates; the presence of glued metal anchors.

The results of the studies show that the shear strength increases, in the test specimens of concrete with greater compressive strength. The shear strength is increased in the contact seams when processing specimens by connecting emulsions and repair solutions. The use of anchors also increases the shear strength in the contact seams, but the strength gain is not satisfactory, it is less than the calculated value.

Key words

contact seam, shear strength, teamwork, anchor, binding substrate

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