In-depth knowledge of an existing structure requires an integrated diagnostic approach. No single technique can fully describe geometry, materials and condition: a reasoned combination of different methods builds a reliable knowledge model.
“There is no universally best diagnostic technique. There is a method best suited to the information that needs to be obtained.”
Each method answers a specific diagnostic question. Existing structures may differ from the original design: incomplete documentation, alterations over time, material deterioration or new intervention requirements call for an in-depth understanding of the structure's actual condition.
An effective diagnostic campaign therefore starts with the questions that need answers:
Existing structure
Knowledge model
Integrated diagnostic methods
Geometric investigations
Position, levels and internal geometry of elements.
Material investigations
Physical and mechanical properties of materials.
Volumetric investigations
Reconstruction of the interior of a structural element.
Deterioration investigations
Anomalies, discontinuities and condition assessment.
Each method answers a specific technical question. The main diagnostic objective and applicable materials are identified for each technique; the cards link to dedicated technical guides.
An electromagnetic-wave method for identifying internal elements, geometry and anomalies, with high productivity over large surfaces.
Diagnostic objective
Identification of internal elements, geometry and anomalies.
Applicable materials
A targeted electromagnetic investigation to locate near-surface reinforcement and estimate concrete cover.
Diagnostic objective
Locating reinforcement and estimating concrete cover.
Applicable materials
Analysis of elastic-wave propagation through a material to assess homogeneity and identify internal anomalies.
Diagnostic objective
Assessment of material homogeneity and identification of anomalies.
Applicable materials
An advanced technique that analyses reflections of ultrasonic waves generated in the material to construct a three-dimensional or sectional representation of an element's interior.
Diagnostic objective
Identification of voids, cracks, debonding and internal anomalies using 3D or sectional imaging, including with access from one side only.
Applicable materials
A combined method integrating rebound index and ultrasonic pulse velocity to estimate concrete's mechanical properties indirectly.
Diagnostic objective
Indirect assessment of concrete's mechanical properties through experimental correlations.
Applicable materials
Analysis of an element's surface temperature distribution, effective over large surfaces and capable of integration with drone surveying.
Diagnostic objective
Identification of surface anomalies and discontinuities through thermal response.
Applicable materials
Testing of welds and components; for civil structures, local investigations in specific cases and suitable operating conditions.
Read moreDifferent methods used to answer complementary diagnostic questions.
Bridges and viaducts are complex infrastructure, where understanding the internal condition of structural elements may require different diagnostic methods.
Techniques must be selected according to the diagnostic question, the structure's characteristics and operating conditions.
In specific investigation programmes, combining GPR, ultrasonic tomography and digital radiography can provide complementary information about the internal configuration of structural elements.
Application case
In 2019, Novatest Engineering carried out a demonstration campaign at the Via Mario de Bernardi viaduct near Fiumicino Airport using three non-destructive methods: GPR, ultrasonic tomography and digital radiography.
The aim was to investigate selected construction elements of the viaduct and demonstrate the potential of the different investigation methods.
The approach's value lies in obtaining different, complementary information, selecting each method for the specific diagnostic question.
Example investigation strategy
GPR
Location and geometry
Ultrasonic tomography
Analysis of internal discontinuities
Radiography
Detailed local investigation
Correlation of information
The diagram shows an example investigation strategy, not a mandatory procedure: the choice and sequence of methods depend on the diagnostic question and the structure's condition.
A diagnostic strategy does not mean using more techniques indiscriminately.
It means selecting, correlating and exploring the information needed to understand the structure better.
Documented experience
At the Tronto IV viaduct on the SS 4 Salaria, Novatest Engineering conducted a radiographic investigation campaign aimed at observing cavities, internal honeycombing and the condition of reinforcement, with particular attention to prestressing strands.
The campaign comprised 478 radiographic acquisitions.
Read about methods, investigation strategies and application cases developed by Novatest Engineering on existing infrastructure.
Novatest is not simply a provider of test execution: every diagnostic campaign is a process of consultancy and client support, from problem analysis to decisions following the investigation.
Working with the client to define the information actually required.
A reasoned proposal of appropriate methods, rather than simply the equipment available.
Field investigation using dedicated instrumentation.
Processing and reconstruction of datasets.
Integrated technical interpretation of results.
Reports, drawings and support for subsequent decisions.
Integrating GPR, ultrasonic tomography and reinforcement mapping identifies embedded elements, discontinuities and internal anomalies in concrete, reducing diagnostic uncertainty and strengthening technical decisions.
The choice of diagnostic method depends on the technical problem, the material and the information required. Novatest engineers can support you in defining the most effective strategy.