DFOS measurements for strain analysis of anchorage zone in 57-year-old posttensioned precast girder using static and high-frequency approach
The article presents the results of static and high-frequency strain measurements of a 57-year-old post-tensioned crane girder, dismantled from one of the production halls. The anchorage zone and transmission length of the tendon related to the quality of cement injection around the prestressing tendon were analyzed.
Smart prestressed concrete girders with integrated composite distributed fibre optic sensors (DFOS): monitoring through all construction stages
The paper discusses a real case study of prestressed concrete girders, equipped with composite DFOS strain sensors during production stage. Composite sensors with monolithic cross section (unlike commonly used layered sensing cables) were embedded into the concrete. Bonding properties responsible for accurate strain transfer mechanism were ensured by external spiral braid, analogously like for composite reinforcing bars.
Smart Composite Rebars based on DFOS Technology as Nervous System of Hybrid Footbridge Deck: A Case Study
The paper presents the concept and application of the smart pedestrian footbridge, equipped with DFOS strain sensors called EpsilonRebars. These sensors, in the form of composite rods being simultaneously the structural reinforcement for the concrete deck, were placed along the entire span of nearly 80 m.
Possibilities of composite distributed fibre optic 3DSensor on the example of footing pulled out from the ground: a case study
This paper discusses in situ application of unique (patented) composite DFOS displacements sensors (3DSensors), which were embedded into the ground layers and compacted around the footing. The research was conducted to observe the potential slip plane generated during the vertical pulling of the footing out of the ground.
Application of Distributed Optical Fibre Sensor for Strain and Temperature Monitoring within Continuous Flight Auger Columns
In presented case study the analysis of continuous flight auger (CFA) column was described based on the strain and temperature measurements carried out continuously over the length of 12 m. The measurements were done during the load tests, but also in the early-age concrete, when thermal-shrinkage strains appeared.