On the issue of calculating the cornice unit of a monolithic reinforced concrete frame of frame-type buildings
Abstract
On the issue of calculating the cornice unit of a monolithic reinforced concrete frame of frame-type buildings
Incoming article date: 22.10.2024The article discusses the results of the analysis of the stress-strain state of the junction of the column and the beam of a monolithic reinforced concrete frame - in particular, the cornice nodes of the outer columns, which have an L-shape. In these nodes, part or all of the tensile (upper) reinforcement of the beam, bending along a certain radius R, passes into the column. The subject of the study is the stress state of concrete in the frame node, as well as the features of the operation of the curvilinear section of the tensile reinforcement. The study of the features of the concrete operation was carried out by setting up a computational experiment. Modeling was performed in the Lira-SAPR software package. The characteristics of the model (finite element scheme) and the main results of the calculation are given - the distribution and numerical values of stresses. To assess the actual work of the tensile reinforcement of the node, an analysis was made of the influence of the loading history of the reinforcement bar - its plastic bending to give the required outline. It was established that the stress state of concrete of a bisecting section differs fundamentally from the stress-strain state of concrete in normal cross-sections of a beam and a column. Taking into account the loading history of the reinforcing bar (preliminary inelastic bending) allowed us to conclude that, with the same tensile force, the deformations of a pre-bent bar exceed the deformations of a rectilinear bar. Obviously, this circumstance leads to an increase in the crack opening width.
Keywords: ramny node, reinforced concrete, reinforcement, stresses, deformations, bisector section, normal section, plastic bending, bending radius, loading history, finite element, Lira-SAPR