Analysis of Height Stability of Object Points of Monolithic Construction

Abstract

Geodetic measurements aim to monitor the behaviour of objects and prevent various degrees of non-functionality or destruction. By measuring vertical movements, the height stability of the monolithic building is monitored concerning the previous stages of measurement. The measurements were carried out using a digital levelling instrument, the Leica DNA03 and invar code bars GPCL2 with a length of 2 m. The object points were mainly stabilized in the supporting structure of the building, but stabilization in the ceiling was also necessary in problematic areas. Object points in the ceiling were measured using a special metal hanging holder for levelling rods. After the initial verification of the measured elevations, and whether they meet the accuracy criteria, processing followed by the application of the Gauss-Markov model based on the method of least squares corrections. The estimates of the unknown parameters from the stage measurements were used to calculate the height differences of the observed points, which characterize the behaviour of the monolithic object. Significant height changes were detected based on the accuracy of the estimated heights, determining whether they represented significant drops or just an accumulation of measurement errors. The height changes of the object points were graphically visualized in 1D as time series of decline and in 2D as isolines of vertical displacements based on the floor plan of the monolithic building.