Horses for Courses 2022-PPT Presentation

PPT Presentation

Pdf Summary

The panel discussion examined how to select the most appropriate non-destructive testing method for evaluating unknown foundations. Although testing technologies have advanced, engineers must understand each method’s limitations rather than choosing by cost alone. Results should be interpreted by trained specialists, supported—but not directed—by software, and independently of who commissioned the testing.

Assessment needs may include foundation length, integrity, type and material, location, and details such as reinforcement, anchor bolts, diameter, or pile-cap dimensions. Foundation types range from drilled shafts and piles to mats, shallow footings, and complex buried systems.

Methods discussed included:

- <strong>Echo testing (Impulse Echo/Pile Integrity Testing and Impulse Response):</strong> Relatively fast and economical; can estimate length and identify defects. These methods generally require direct access to the foundation and may be limited by complex soils, variable cross-sections, multiple reflectors, or limited penetration depth. Impulse Response can also assess stiffness and aspects of concrete quality but is sensitive to shaft-head and soil conditions.
- <strong>Parallel Seismic:</strong> Can estimate foundation length and help identify material, including for existing structures. It requires a nearby borehole and an impact point on the foundation or structure, is slower than echo testing, and is considered reliable.
- <strong>Specialized methods:</strong> Ground Penetrating Radar is suited to shallow or mat foundations and reinforcement surveys. Magnetic/electromagnetic tools can measure steel-pile depth or rebar-cage depth but require a nearby borehole. SASW is used for lateral and shallow foundations, while borehole radar is most effective for steel foundations.
- <strong>Other tests:</strong> Crosshole sonic and gamma-gamma logging require access tubes; thermal integrity profiling applies to fresh concrete and offers no useful information after it cools.

The central message was that no single method suits every foundation. A sound test program matches the method to the foundation, access conditions, and information required.

Keywords

non-destructive testing

foundation assessment

echo testing

parallel seismic

ground penetrating radar

impulse response

pile integrity testing

borehole radar

crosshole sonic logging

foundation integrity