A case study of the use of GPR for rehabilitation of a classified Art Deco building: The InovaDomus house

Abstract

Ancient buildings in historical town centers can be protected by Cultural Heritage legislation, thus implying that any rehabilitation must respect their main architectural features. These concerns also apply to Modern and Contemporary buildings, in particular if they are important examples of architectural styles from those periods. These extra problems, or motivations, add to the inherent structural delicacy of ancient building restoration that requires detailed knowledge of the building foundations, characteristics and materials, modification history, infrastructure mapping, current pathologies, etc., all relevant information for an informed rehabilitation project. Such knowledge is seldom available before the actual rehabilitation works begin, and the usual invasive preliminary surveys are frequently expensive, time-consuming and likely significantly alter/damage the building's main features or structural integrity. Hence, the current demand for indirect, non-invasive, reliable and high resolution imagery techniques able to produce relevant information at the early stages of a rehabilitation project. The present work demonstrates that Ground Penetrating Radar (GPR or Georadar) surveys can provide a priori knowledge on the structure, construction techniques, materials, history and pathologies in a classified Modern Age building. It is also shown that the use of GPR on these projects requires carefully designed surveys, taking into account the known information, spatial constraints, environmental noise, nature and dimensions of the expected targets and suitable data processing sequences. Thus, if properly applied, GPR produces high-resolution results crucial for sound engineering/architectural interventions aiming to restore and renovate Modern and Contemporary buildings, with (1) focus on the overall quality of the end-result, (2) no damage inflicted to the existing structure, (3) respect of the building's historical coherence and architectural elements and characteristics, that is, its Cultural Heritage value. Most of the findings and applications discussed in this work can be seen as an approximation to model studies, so that, relevant information can be drawn from the different investigated situations. Therefore, owing to the nature and the range of the problems encountered in this case study, it is also expected that the presented GPR data and interpretation will provide important clues and guidance in the planning and investigation of similar projects and problems.

Analysis and Modeling of GPR Signals to Detect Cavities: Case Studies in Morocco

“…Cavity detection has been considered one of the primary targets in geophysical prospecting, representing a principal goal for the prevention of risk. For example, cavity detection in urban areas is important to prevent accidents related to possible collapses, and in archeology, these cavities are even more important [9]. Most of the techniques proposed lie in the detection of water or air-filled voids whose physical properties (density, electrical resistivity and conductivity, dielectric constant, magnetic susceptibility) are considerably different from the host sediment or rock [3].…”

A comprehensive study for moisture control in cultural heritage using non-destructive techniques

“…Many cultural heritage studies conclude with recommendations on monitoring the risks to which a cultural heritage asset may be subject as part of a preventive conservation strategy or to avert or minimise damage [11][12][13]. With the use of non-destructive or minimally invasive techniques [14], damage can be detected in an incipient stage and specific action can be taken.…”

IRT and GPR Techniques for Moisture Detection and Characterisation in Buildings

“…Interesting results are also found when mapping water leaks in the subsurface with GPR [ 36 ], showing that water distorted the signal due to an increase of the medium permittivity below the position of the leak in two different forms: (i) a reduction of the reflection amplitude beneath the leak position because of the attenuation of the electromagnetic waves traveling through the wetter area and (ii) a delay in the reflection time due to a decrease of the wave velocity. Other relevant studies regarding the analysis of the different amplitude values of the reflected pulses are found: (i) the effect of moisture on two different walls of an early 20th century building composed of both ancient adobe and modern bricks [ 37 ], (ii) the presence of a strong anomaly associated to the presence of a high amount of moisture in a specific part of an interior vault of a room from the early 19th century [ 38 ], (iii) the generation of moisture maps of the walls and floor of a residential basement made of lightweight aggregate blocks [ 39 ], and (iv) the evaluation of moisture levels in a thick travertine wall of an ancient church in Italy thanks to the “time-stretched signal”, “ringing” effects, and variations in the signal amplitudes [ 40 ].…”