Verification of floor planarity by trigonometrical measurement of heights on a 5-storey monolithic building

Abstract

Currently, trigonometric levelling is becoming increasingly widespread, mainly due to the increase in accuracy of stations that can measure angles with seconds and distances with submillimetre accuracy. The paper deals with the analysis of the sources of errors affecting the accuracy of results. It also describes a design of observational methodology that excludes or significantly reduces the impact of systematic errors or other errors occurring during the measurements process, in order to achieve the highest accuracy of the determined height difference. Therefore, under certain conditions, it is possible to achieve the accuracy of determining a height difference of up to 0.10 mm using this method. Furthermore, by the practical example, the description of the use of trigonometric levelling from the centre when verifying the floor planarity of a 5-storey monolithic building is also presented in the paper. The skeletal structure made of concrete floors supported by beams is the main structural element of the building. The finished floors showed visible deformations. Therefore, before the continuation of further construction, the control height measurement of all above-ground floors was necessary in order to ensure the safety in terms of stability and subsequent correction of the project. The resulting floor planarity is graphically visualised and analysed.

Keyword : trigonometric levelling, propagation of covariances, accuracy analysis, floor planarity, colour hypsometry, cross-sections