Measuring the effects of blast-induced vibrations on buildings with fibre Bragg gratings

Abstract

This paper discusses the application of a fibre optic system to determine and evaluate the effects of blast-induced vibrations on buildings. For the first time in quarrying, fibre Bragg gratings (FBGs) were used to measure wall strains and crack displacements in a residential structure at varying time intervals. The comparison of the results with measurements of common short-term vibration geophones shows the distinct advantages of this fibre optic technology. Other factors, such as temperature, geologic conditions, solar radiation and other seismic activities, can also influence the crack response of buildings which cannot be investigated with common geophones. In the case study presented, the strong influence of the outside temperature on crack response was proved; blast vibrations turned out to have only a minor influence. The results of this study show that, with the use of FBGs every dynamic strain and movement of building superstructures can be measured and analysed and the influence of blasts evaluated.

Keywords:

• Blast vibration
• Fibre Bragg grating
• Crack displacement