FIBRE BRAGG GRATING STRAIN DATA FROM A CONCRETE JACKING PIPE

Microtunnelling or pipe jacking (PJ) is the preferred method of utility pipeline construction in congested urban environments due to its minimally disruptive nature. In this study, a 1490 mm outer diameter reinforced concrete (RC) jacking pipe was instrumented for incorporation within a 297 m long curved PJ drive as part of the Athlone Main Drainage Scheme in Ireland. Fibre Bragg grating (FBG) strain sensors were embedded at the four cardinal points of the pipe to measure axial and hoop strains. Additionally, two vibrating wire strain gauge pairs were installed at two cardinal points. In this paper, data collected from both sensor types during jacking are compared, and a preliminary analysis of the axial FBG strain data is provided.