EXPERIMENTAL MEASUREMENTS OF TOWER CONSTRUCTION TILT USING ELECTRONIC TACHEOMETER

Modern tendencies for assessment of high-rise building deformation state presuppose creation of automated and regular monitoring while using highly-accurate space positioning systems (GPS-systems), a robotic electronic tacheometer, highlyaccurate inclinators (Leica Nivel210/Nivel220-model) with measuring accuracy of tilt angle up to 0.09 s, Geomos software complex (Leica Geosystems). Automated system for deformation monitoring requires significant time and material expenditures, special training of specialists so simpler methods and criteria for assessment of building deformation state are also considered as rather actual for this purpose.There are more than ten conventional methods for determining building tilt. All these methods are based on angular measurements from the fixed base while using highly-accurate theodolites. The methods are rather labor-consuming and they do not provide operational efficiency and accuracy in measurements. Introduction of electronic tacheometers with large radius of refractorless measurements of distances has made it possible to calculate coordinates on the building surface with high accuracy and at various sections (heights) that results in possibility to obtain 3D model of the building surface. Leica TCRA1201 tacheometer has been set at the good visibility point of a tower construction, device orientation and plane coordinates of the temporary point have been determined with the purpose to assess a tilt value of an exhaust stack having 150 meter height. Then 3D coordinates of six points on the building surface have been measured for every stack section. After that these points have been projected on the horizontal plane. LISCAD PLUS software complex has been used for processing and interpretation of geodetic data.The proposed method permits to obtain data for determination value and direction of a tower construction tilt, immediately carry out in-situ measurements and obtain final results in the automatic mode of LISCAD PLUS software complex using only one point of the tacheometer setting. The method does not require any preliminary laying and subsequent preservation of fundamental geodetic points (bases) and it can be applied for any configuration of tower constructions.