Monitoring of the elements stability of building constructions by means of example of vertical elastic rod of high flexibility

Abstract

The article is related to the field of geodetic and engineering construction monitoring of building structures in the form of rod systems. It investigates the measurement accuracy of the compression deformation of the rod.  As an example, there is considered a vertical rectilinear rod of high flexibility, loaded with a longitudinal axial force. Experience demonstrates that the rod, under the influence of an axial compressive load not exceeding the permissible design values, retains its original form of equilibrium and stability. At the same time, it works in the field of elastic compression deformations. As the load increases to its critical values, there occurs a particular state of the element when the form of equilibrium becomes unstable, and at any moment, it can turn from a straight line into a curvilinear one with a slight external influence or as a result of position errors. This is accompanied by large displacements and permanent deformations. The importance of monitoring is noted when a building structure with similar constructions, for example, is situated in the area of development of negative natural and anthropogenic processes. As a result, the load on some elements may increase to critical values due to uneven horizontal and vertical displacement and inclination of the structure, including vibrations, etc. Attention is focused on the fact that the complex of engineering and technical measurements should show, with the necessary completeness, reliability and accuracy of the value, the nature and dynamics of changes in the external load on the elements of the building structure, changes in internal forces and stresses in them, the development of deformations (changes in the size and shape of equilibrium). There is explained the accuracy with which it is necessary to measure the displacement of the rod end during the deformation. There was derived the dependence with the help of which it is possible to see the root-mean-square error of the displacement measuring that depends on the choice of the maximum stress deviation in the sections of the rod made of a certain material.  There is laid out the calculation of the maximum stress deviation based on the stability and flexibility of the rod.