Ground-penetrating radar and geotechnical analyses to investigate the foundation settlements of an indiana house in NW Spain

Abstract

Settlements represent one of the most dangerous causes of degradation of the stability and preservation of buildings. This work presents a Ground-Penetrating Radar (GPR) survey aiming to investigate settlement problems that compromise the structural integrity of an Indiana-style house built in 1933–36 (Cabanas, northwest of Spain). From a simple visual inspection, it was possible to observe external damage like cracking, subsidence and bulging in the building façades, retaining walls and pavements. The GPR survey was conducted using a ProEx system with a 500 MHz antenna, which allowed for the production of an overall image of the subsoil until a depth of 3–4 m. The GPR data allowed for the detection of subsidence, voids and poor soil compaction, which made easier the identification of building settlements. The GPR interpretation was then validated with geotechnical prospection (sampling and dynamic probing superheavy (DPSH) tests), which showed good agreement between techniques. The better knowledge of this settlement phenomena was promising for the engineers and architects engaged in the design of conservation activities for such a singular architectural heritage.