Which term describes the study of soil properties and groundwater for bridge foundations?

• A. Geotechnical surveys
• B. Hydrotechnical surveys
• C. Topographic surveys
• D. Seismic surveys

Answer: (A)

Investigations into what lies beneath a bridge site, particularly how the soil behaves and where groundwater sits, are the bread-and-butter of geotechnical engineering. Geotechnical surveys are specifically about collecting and interpreting data on soil properties—such as grain size, density, shear strength, compressibility, and permeability—as well as the groundwater regime (water table level and pore pressures). This information is essential for designing safe foundations, determining bearing capacity, estimating settlement, and deciding whether piles, shallow footings, or other foundation types are needed.

That’s what sets geotechnical surveys apart from the other terms. Hydrotechnical surveys focus on water-related structures and hydraulic behavior, topographic surveys map surface features and elevations, and seismic surveys study subsurface structure and properties related to earthquakes.