LiNAFoS - Ground anchors: Numerical analysis based on in-situ investigations using high precision fiber-optic sensors

A significant number of ground anchors is used in Austria in construction and maintenance of infrastructure projects. However, there is still a lack of knowledge of details in the load transfer from the anchor to the ground and consequently on the bearing capacity of these anchors. Design procedures rely on inadequate measurements, at least when latest available technology is taken into account, and are not very reliable due to uncertainties in input parameters. By using fiber optic sensor technology it is now possible to measure quantities in situ, which can be directly compared to the results of numerical analyses, which will lead to a significant improvement of the numerical models. Three in situ tests in different, but as homogeneous as possible, ground conditions will be performed, which is essential in order to obtain a good assessment of the bearing capacity of anchors in the future. In a preliminary test it could be shown that application of sensitive sensors in situ is possible and very accurate readings could be taken and analysed. Up to now unknown features could be identified leading to a significant potential for improvement for optimization and testing of ground anchors. However, despite the excellent performance of the measurement system there is still a need for clarification of some issue concerning the fiber optic sensors in order to minimize measurement uncertainties and establish methods for long term measurements, which are currently not available. The strength of this proposal is certainly that partners with strong competencies in construction, measurement systems and theoretical analysis work together in a team. This will lead to a significant gain of knowledge of the load displacement behaviour and the bearing capacity of ground anchors.