Full-scale testing of vertical keyed joints of reinforced concrete wall panels with flexible loop connections in shear

The most significant elements of large-panel buildings are vertical interpanel joints, which ensure joint operation of building structures. The interpanel joints should be of necessary strength and stiffness to take up shear and tensile forces transmitted to them by the adjacent wall panels. In addition to welding joints, monolithic looped joints are also currently used, including those with flexible wire-rope loops. A special role in the work of such shear joints is played by the concrete mixture, which is used for joint grouting. This paper presents an experimental study of the work on the shift of vertical interpanel keyed joints with wire-rope loops, monolithic with fine-grained concrete of a special composition, developed by OOO “BETOTEK”. The research study has been conducted using full-scale samples of joints of two types: linear - conjugation of two external panels located in the same plane, and T-shaped - conjugation of two external panels located in the same plane, with an adjacent internal panel in the perpendicular direction. During the course of the tests, the mutual displacements of the panel elements and cracks in the monolithic seam have been detected. The samples have been loaded with a static load in steps up to their destruction. As a result of the tests, a two-stage operation of the joint (before and after cracks appearing in a monolithic seam) has been determined; and the characteristics of the joint necessary for the calculation and design of buildings, such as crack formation force, joint bearing capacity and joint stiffness parameters have been specified. A significant underestimation of the values of the force of cracking and the stiffness of the joint before cracking, determined by the formulas of the current regulatory documents, in comparison with the values obtained as a result of the tests, has been revealed.