The article discusses a new nodal connection of thin-walled and cold-formed profiles with a trapezoidal part of the wall using a through stop bushing. The use of this constructive solution allows to place additional bolts in the area of the concave part of the wall of a thin-walled profile, thereby including this area in work. It is noted that the invention in comparison with analogs allows to simplify the assembly process of the node by fixing the position of the sleeve when using a broadened part on one side of the gusset. At the same time, in order to effectively resist the loss of local stability of the wall of a thin-walled and cold-formed profile, it is proposed to arrange adjacent bushings with sides in the opposite direction. Issues of deformability of the wall of a thin-walled and cold-formed profile are studied when additional rows of bolts are installed in the trapezoidal part of the wall due to the developed design solutions: using a through bushing, a through bushing with a stop and in the absence of bolts in the area of the trapezoidal part. The paper presents the results of displacements of the wall under the influence of a compressive load with different variations of bolted nodal joints. A comparative assessment of the efficiency of nodal connections from the point of view of resistance to loss of local stability has been carried out. In result, it is revealed that a bolted nodal connection with the installation of additional bolts in a part of a trapezoidal wall, due to the use of a through bushing, can reduce deformability by 15% and by 33% when using a through bushing with an emphasis in relation to a connection with a two-row bolting

With the development of technologies, the number of accidents related to construction machines in one way or another increases. The article deals with the analysis of the causes of accidents of the VIPO 32-01 auto-hydraulic lift. According to the results of engineering and technical expertise, the cause of the accident was a break in the connection of the two upper traction chains with anchor bolts fixed to the main section of the boom. During this break, there was a spontaneous movement of the third and fourth sections of the telescopic boom of the auto-hydraulic lift. The main reason for the lack of strength of anchor bolts of the upper traction chains according to the results of the research was the use of steel grades with insufficient strength characteristics in their manufacture. Material did not have sufficient load-bearing capacity in the cross sections of the eyes of anchor bolts intended for fastening chains, for the perception of the calculated forces in the traction chains.

The article presents the results of analysis of the stress-strain state of the developed new nodal solutions for fixing cable ties in collapsible spatially strained structures, since the existing nodal solutions are not intended for connecting cable ties. During operation under extreme conditions for the structure (sudden gusts of wind, dynamic effects), it is necessary to ensure the reliability of the nodal connections of the cable ties with the struts. It is also important to maintain the speed of building structures. The mentioned ideas influence on additional moments that worsen the work of the temporary structures node. Stress-strain state analysis of the original and newly developed node was performed on the basis of both computer modeling and natural experiment, the results were compared. In the course of the conducted research, the most stressed zones in the created nodes were identified, as well as the reasons for the destruction of newly created nodes.

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.

Large-scale mass events (sports, entertainment, etc.) require safe and high-quality organization of the visual and stage sector, so there is a need for pre-fabricated and mobile rod structures. To solve such problems, it is convenient to use the Layher system of modular building structures. The criterion for design failure is the failure of one of the most loaded elements, even when the entire system as a whole still has some resource. Compensating devices can be a solution to this problem. This study solves the problem of redistribution of forces in the rods using compensating devices, taking into account the stress state of the rod system. In the event of failure of one or more elements, their internal forces are redistributed between adjacent elements in proportion to their stiffness, so spatial rod systems can fairly well resist progressive destruction. However, the destroyed element does not carry any further load and adjacent elements can also fail. Compensating devices leave overstressed rods in operation and thus increase the load-bearing capacity of the rod system. The invention relates to the field of construction and mechanical engineering, namely to rod metal structures and their elements that work on tension or compression, primarily in statically indeterminate systems. The purpose of the invention is to obtain stable axial forces in a limited range separately for compression and stretching with the possibility of adjusting their size and length of the element. This goal is achieved by the fact that in the process of manufacturing the force limiter, which includes coaxial rod elements with a collet clip, the contact surfaces are made with ring waves (teeth), which can have a sinusoidal, triangular and trapezoidal profile with different angles of inclination of the sides. The height and pitch of the ring waves are assigned from the conditions for performing the calculated range and speed of loads, and the angle of inclination of the profiles from the conditions for ensuring different rates of change in forces (compression/stretching). Arbitrary schemes have been studied, the use of compensating devices in which allows reducing the metal content of the structure by 20%. A compensating device was developed and calculated. An experiment was conducted to identify the redistribution of forces between elements when using compensating devices: the results generally coincide with theoretical calculations.