The test specimen is a reinforced concrete specimen, designed and constructed at the CSIR-Structural Engineering Research Centre (SERC), exclusively for the data generation and validation of different NDT techniques.
- It consists of two slabs of sizes 4.15m x 4.15m (bottom slab) and 3.0m x 3.0m (top slab with cantilever projection at one end) with beams and columns.
- The entire block is supported on four pedestals at a height of 1.2m to have access for the bottom slab.
- The top slab is made with two different thicknesses (150mm and 250mm) and bottom slab with three different thicknesses (150mm, 300mm and 400mm) for validating the thickness measurements using NDT methods. At the edge, the slab is tapered.
- Top slab is provided with construction joints, different sizes and shapes of honeycombs, PVC conduits, cracks for their identification and quantification.
- Bottom slab is provided with bolt holes, PVC inserts and conduits to locate and quantify the defects.
- Both the slabs have various reinforcement ratios to locate the position of the bars, spacing etc.
- Beams are provided with different diameter of reinforcements with different spacing of shear reinforcements and different cover thickness.
- Beams are provided with ducts to study the grouting problems in prestressing ducts. Columns are provided with different diameter of reinforcements with different spacing of lateral ties and different cover thicknesses.
Scale NDT Test Specimen Details of inserts and pipes in Second floor slab
Processing of Data Collected using GPR
REFLEXW and RADAAN are the programs used for the processing and interpretation of reflection and transmission ground penetrating radar (GPR) data collected from the specimens using manual scanning or the automated scanner.
The 3D data-interpretation module is used for displaying x-,y- or z-slices
SERC NDT Specimen Data – Raw, Migrated and 3D Plot
The advantage of GPR compared to Ultrasonic pulse echo technique is that larger surface area can be examined in short time because of the continuous measurements along a surface
Top Floor showing the absence of reinforcements, honeycombs and PVC
Oscilloscope, Wiggle and Linescan Plot showing Embedded Steel Plate