Demountable Rod Structures with Flexible Connections Ensuring the Reliability and Safety of Construction Objects

Abstract

Individual walls of structures based on wedge-type scaffolding can be different in height and are often used as enclosing structures for different cultural and sporting events. Usually, such structures are covered in the longitudinal direction with an awning cloth on both sides, which is why they take on the full wind load from the entire area of the awning. When calculating such structures, the wind load is the determining load. In practice, these structures are built according to the recommendations of the manufacturer’s catalog of scaffolding, and they are repeatedly statically indeterminate systems with a large number of unloaded elements. This increases the material consumption of the structure and increases the cost of transport and installation work. In structures made of modular scaffolding, diagonal elements are used to give spatial rigidity to the structure, to reduce the calculated length of vertical elements, and to perceive the shift movements of the cell caused by uneven vertical movements of adjacent posts and horizontal loads. A structure with a full set of diagonal elements has a large number of weakly loaded elements. In this regard, it is possible to perform the so-called «discharged» construction scheme for more efficient use, replacing rigid diagonal elements with cable ties and reducing the number of diagonal elements in the longitudinal direction. The main task of the work is to analyze the stress-strain states of both the original system with rigid diagonal elements and systems obtained by partially replacing standard diagonals with flexible connections in the form of pre-stressed and non-pre-stressed cable ties. In order to study the actual operation of elements of rod collapsible structures and improve their design solutions, an experimental study of a fragment of the Layher system with cable ties was performed. Based on the experiment, it was determined that the actual movements when using flexible connections differ significantly from the calculated ones. The reason for the discrepancy is the deformation of the elements in the attachment points. To increase the rigidity, the design of the attachment unit needs to be changed.