Features of the monolithic frame joint with cured reinforcement
Abstract
Features of the monolithic frame joint with cured reinforcement
Incoming article date: 02.11.2025The article presents the results of an analysis of the stress-strain state and the failure mode of a frame joint connecting a monolithic reinforced concrete crossbar with a column in a frame structural system. The distinctive feature of the considered joint is that part or all of the tensioned (top) reinforcement of the crossbar, bending with a certain radius R, continues into the column.
The research was conducted through a computational experiment. The modeling was performed in the LIRA-SAPR software package. The issue of calculating the normal sections of the joint from the standpoint of SP 63.13330 (Russian Building Code) using the formulas for eccentric compression is considered. An analysis of the joint failure modes during a physical experiment is performed. The dependence of the radial pressure exerted by the curved reinforcement on the concrete on the stress in the reinforcement and its bend radius is determined. The bisectoral section of the joint, represented as a rectangular plate of unit thickness cut by two planes perpendicular to the mid-surface of the joint, was adopted as the calculation object. The calculations were performed using a nonlinear formulation. Recommendations are made for limiting stresses in the reinforcement when calculating the joint according to SP 63.13330. A model for calculating joint failure due to spalling of the side faces from the radial pressure of the curved bars is proposed.Keywords: reinforced concrete frame joint; curved reinforcement; stress-strain state; joint failure; finite element analysis; LIRA-SAPR; concrete spalling; bisectoral section; normal section; bend radius