Prototype of 2D-scanning system for automated measurements on concrete surfaces with impulse radar, ultrasonicecho and impact-echo : Sustainable Bridges Background document SB3.6

Non-destructive testing methods are preferably used for the inspection of concrete constructions. These methods are applied for existing structures and for new constructions in the frame of quality assurance. When the building element is accessible from one side only, echo methods as ground penetrating radar, ultrasonic echo and impact-echo are applied. Examples for testing problems to be solved with echo methods are • Localisation and measuring the concrete cover of reinforcing rebars and tendonducts • Measuring the thickness and geometry of structures • Localisation of honeycombing and compaction faults • Inspection of tendon ducts, especially grouting defects and compaction faultsaround them • Localisation of delaminations at multi-layered structures. The main difficulty is, that the sensors have to be applied manually. The methods are thus not applicable for large areas in manner of high quality and with dense grids. The output of D3.6 is the prototype of a 2D scanning system. State of the art before the project was manual application of sensors. Some very early prototypes of scanning systems existed, but were either bulky or not ruggedized for on-site use. The systems developed in the project (section 3 and 5) are now able to be used at railway bridges, they save time and increase accuracy and data density and don’t interfere with railway’s signaling or communication. Automated inspection combining impulse radar, ultrasonic-echo and impact-echo methodsis now available with the BAM 2D scanning system. The modular system is adapted and tested with the special demands on railway concrete boxgirder bridges. The system allows the locating of reinforcement and tendon ducts as well as the detection of compaction faults, injection faults and honeycombing with a high accuracy inpositioning and reproducibility in a yet unknown speed. The main issue of this report is to show that the target specifications, the prototype of anautomated scanning system, were achieved. Evaluation of measurement results will be discussedin other deliverables of WP3.EC Sixth Framework ProgramSustainable Bridges – Assessment for Future Traffic Demands and Longer LivesTIP3-CT-2003-001653