After a partial collapse, checking the rest of the building

Part of a slab in one room had collapsed. We were called to inspect the remaining rooms, slabs and elements and establish whether the same conditions existed elsewhere. The client needed to know which areas to release, which to prop, and where repair had to start.

The building was occupied and partly distressed, so nothing invasive was possible, and the answer was needed quickly. Moisture varied room to room, which shifts the depth reading if a single calibration is used across the floor.

Gridded the elements from the soffit and, where reachable, the top surface, calibrating each element separately. Delamination gives a three part signature that can be looked for directly: a flat echo with air type polarity, ringing repeats at even intervals, and loss of the bar response beneath it. Depth slices at and just below the reinforcement level showed those zones as continuous areas in plan rather than scattered bright spots.

Delaminated zones and reinforcement irregularities mapped with plan extents and depths, letting the client rectify promptly. The report was explicit about what radar does not answer: cause of collapse and residual capacity require ultrasonic pulse velocity, impact echo and a small number of agreed cores.

The HILTI PS 1000 X-Scan is a three antenna ground penetrating radar system that produces plan view images of concrete, not the single line trace of a covermeter or a rebar scanner. It records a 600 by 600 mm image scan grid in a single set up, extendable to 1200 mm by 1200 mm for larger elements, and detects to a stated maximum of 300 mm in concrete. Default settings assume dry, ordinary concrete, so we acquire in expert mode with the phase of the signal preserved and calibrate the dielectric constant on the element in front of us, processed in PROFIS Detection together with our own MATLAB routines.

Enquiry. Send the element type, thickness, exposure condition and what you need to locate on WhatsApp. Photographs, drawings and any previous scan output help us assess it fast.

Plan. We check access, moisture, exposure and reinforcement congestion against your target, confirm radar is the right test, and schedule the visit.

Scan and mark. Calibrated on the element, scanned in an orthogonal grid, and marked directly on the surface for your coring or cutting crew, same visit.

Report, if needed. Depth slices, plan extents and permissible core diameters, issued as a written report when your project requires formal documentation.