Boštjan Kovačič

DEFORMATION MEASUREMENT OF A STRUCTURE WITH CALCULATION OF INTERMEDIATE LOAD PHASES

Abstract At the Centre for Geodesy of the University of Maribor, Slovenia, we engaged in the measurement and analysis of displacements for the last ten years. We wanted to find the connections between the displacements and the applied loads. Therefore, reliable and accurate results were needed. A reinforced-concrete plate was loaded to 42 kN in pre-calculated steps and the resulting deformations measured by three independent methods. The results were compared to analytical ones. The analyses and calculations of the most suitable method were implemented. An electronic tacheometer, photogrammetry and a pressure length transducer on the hydraulic cylinder were used.

Preparation, Installation and Signal Processing of Strain Gauges in Bridge Load Testing

Practical approach of strain gauges using is introduced. The use of strain gauges and signal processing of measured data at static experimental load testing of a concrete beam are carried out. The ability of the strain gauge sensor to pick up the specific deformation / strain signals during loading is investigated. The Fast Fourier Transformation (FFT) is applied to obtain the signal in frequency domain and reverse FFT to transform the processed signal back to time domain. The measurements are confirmed with some inductive transducers and total station. This approach is tested on 2.7 m long concrete beam in laboratory. A practical use of strain gauges with bridge constructions under complex inspection is described.

Geodetic Measurement of Vertical Displacements (Illustrated with the Slovenian Viaduct)

Today there are a lot of sophisticated methods to measure and analyse a bridge during load tests as a GPS, photogrammetric measurements, laser scanning, etc., The use of an classical techniques as trigonometric hights is still good enough for most demanding field observations. In practice control measurements are performed with the help of geodetic measurements, of which the basic goal is to capture any geometric changes in the measured object, or its displacements and deformations are found. In this article the use of trigonometric hights during a load test on the biggest Slovenian viaduct “Črni Kal” is introduced, displacement measurements on the viaduct and an analysis of results, with particular stress on the accuracy of the calculations.

Geodetic monitoring of suspended particles in rivers

There is a trend in modern approach to the management of space of collecting the spatial data, in order to obtain useful information. In this paper a research of suspended particles in the river Drava and Mura will be introduced. The goal is to connect different fields of water management in countries where the rivers Drava and Mura flows in purpose of water management sustainability. The methods such as GNSS for mapping cross sections of the river, the use of ADCP (Acoustic Doppler Current Profiler) measurement system and water sampling to monitor sediment in the water will be presented.