EXPERIMENTAL STUDY OF SHORT-TERM COMPRESSIVE STRENGTH OF COMPOSITE REINFORCED CONCRETE COLUMNS WITH HIGH-STRENGTH REINFORCEMENT

Abstract

The article presents an experimental study of the short-term compressive resistance of composite reinforced concrete columns with high-strength longitudinal reinforcement of class At-V. The relevance of the study is due to the lack of data on the behavior of composite columns made from concretes of different ages and deformabilities under central and eccentric loading. The aim of the research was to establish the patterns of change in short-term compressive resistance depending on column slenderness, branch joint conditions, and longitudinal force eccentricity. To achieve this, physical experiments were conducted on six composite columns with different branch configurations, accompanied by control cubes and prisms, with deflections and longitudinal deformations of reinforcement measured using strain gauges and dial indicators. Results demonstrated that differences in the deformability of branch concretes lead to uneven stress distribution, increased reinforcement deformability, and changes in failure modes. The study clarified mechanisms of interaction between concrete and high-strength reinforcement in composite sections and highlighted the influence of eccentricity and branch joint conditions on column load-bearing capacity. The practical significance lies in the applicability of the results for the design of precast-monolithic and strengthened reinforced concrete columns in construction and building reconstruction.