Investigation of the Influence of Damage of the Compressed Concrete Zone in Bending Rectangular Reinforced Concrete Elements With Insufficient Reinforcement

Abstract

Abstract. The tendency to use buildings and structures for new purposes is growing every year, which leads to the need to change constructive solutions. In such cases, during inspections, there is a need to analyze the bearing capacity of damaged structures. Damage can occur at various stages of the use of an element in construction: transported, installation, operation, and others. For this period, according to the current standards, the residual bearing capacity is determined by the method of the equivalent element. Thus, the strength of the reduced cross-section is determined (the damaged part is folded back). This calculation excludes from the consideration the zones that perceive the loads, but are located in plane damage. Currently, studies of the effect of damage on the residual strength of elements are constantly increasing, taking into account their expediency. Research is more focused on typical elements such as beams and columns. The compositional properties of reinforced concrete elements significantly increase the number of factors that must be taken into account when performing experimental and theoretical studies in this area. The damage itself, depending on their type and characteristics, has a different effect on the strength of the element. There is also a need to take into account additional variations in external influences on the element in addition to damage, such as: change in the load level, the presence of defects, change in the design scheme of the element due to external factors and others. Thus, the priority is, first of all, the study of idealized injuries, with the subsequent use of this base of developments for the study of this damage with additional factors. This article discusses: research on damaged reinforced concrete elements in Ukraine and abroad; the developed test methodology for bending reinforced concrete elements of rectangular cross-section with damage to concrete in a compressed zone with insufficient reinforcement, with variability in changing the width of damage of 20 and 80 mm with a height of damage of 30 mm is presented; the influence of variability of damage in research specimens with insufficient reinforcement on deformability and bearing capacity is reflected; the influence of damage variability on the change in the real height of the compressed zone from the load level is considered; implementation of conclusions on the result of the study.

Calculation Model for Estimation of Residual Bearing Capacity of Damaged Reinforced Concrete Slender Columns

“…One of the important factors affecting the bearing capacity of reinforced concrete structures is the depth of damage and its combination with the shape of the columns; in works [11,12], their combined effect on the bearing capacity was considered. In [13], the relationship of three factors affecting bearing capacity was considered, namely taking into account the influence of the loading option, the reinforcement method, and the level of preliminary damage.…”