Investigative surveys and monitoring activity


The investigative survey: A set of procedures and operations that provide an overview of the structure or the work in question and its state of conservation, the reliability of its constituent materials and elements, related crack patterns and faults - all with the intent of understanding the causes of damage and the determining appropriate remedies.

On the basis of the contract assignment, we can adopt the following techniques:

- Ultrasound scan: A Non Destructive Testing (NDT) method that analyses mechanical waves generated by the elastic deformation of the element under examination.The propagation speed in a material depends on its modulus of elasticity (Poisson coefficient). The stress response and frequency of these waves provide an indirect analysis of the mechanical strength of the material.This technique is used primarily for tests on concrete members.

 

- Tie-rod tensioning tests: determination of the tensile force to which tie-rods are subjected, primarily those fitted in arches and vaults, whose function is to prevent the structure from bowing (bulging outwards).They can be made of wood, iron or steel, they are structural elements and have been used since ancient times.They can be applied during the original construction or in a later stage of structural consolidation.These structural elements, are fastened to walls by means of end-plate anchors which can be of single or double pin type.

 

- Ground probing radar (GPR) inspections: this is an electromagnetic survey method.It consists of detecting reflected radar signals which have been emitted by an antenna, the characteristics of the reflected waves depend on the nature of the materials through which they have propagated.The reflected radiation is analysed, evaluated and recorded.

To simplify interpretation, the signals are transformed to a colour coded representation of the material strata.

 

- Thermographic testing:This Non Destructive Test is based on an analysis in the infrared range of the images generated by an item and detected by an infrared camera. Processing the acquired readings yields a spectrum capable of indicating the causes of a building's deterioration such as water seepage and humidity, or hidden structural elements may be revealed without the need to proceed to destructive sampling or demolition.

 

- pull out:This is a Non Destructive extraction test, a mechanical procedure which allows for the assessment of the quality of concrete structures. It consists of the insertion of an anchor bolt into the concrete to be tested and then its subsequent controlled extraction until the concrete fractures, thus providing a reading of the concrete's average compressive strength.The insertion of the anchor bolts may be done in two ways, when the concrete is still fresh, or when already hardened.Extraction after hardening requires the use of special equipment.

 

- Sclerometric tests: These are Non-Destructive Tests which are carried out by means of a sclerometer to determine the mechanical strength of an element such as concrete, masonry or rock.They are executed directly on a sample of the material by applying a controlled impact from a metal piston and analysing the data provided by the recoil dynamics.

 

- Laser Scan surveys: This method employs a set of sensors that communicate with each other over a laser beam.Processing of the return data makes it possible to estimate three-dimensional models of objects, buildings or structures.The technique can be used to survey building interiors, façade relief elements, or wall verticality.

 

 

- Load testing: These procedures provide an assessment of the correspondence between theoretical and actual data derived from tests performed on the structure under investigation.This type of testing can be performed on horizontal elements such as beams, shelves and floors, or on inclined elements such as pitched roofs or stairs.

The tests can be performed:

- with distributed loads employing water tanks or various various types of ballast;

- with concentrated loads, by means of hydraulic cylinders or suspended tanks.

 

- Tests with flat jacks: tests for diagnosis of masonry buildings and structures that allow for investigations on the conditions and static characteristics of the structure, on the stress state and the elastic modulus.Single flat jacks are used and calculations are performed on the resulting data to determine the state of tensile stress;

Two flat jacks are used to determine the elastic modulus of the material

 

- Visual examinations: a set of inspections carried out on a single structural part or on the entire work complex.The aim of these inspections is to appraise the level of deterioration caused by atmospheric agents, water seepage, stress or structural movement, changes with respect to the original building framework, development and propagation of cracks and fissures etc.In some cases this type of evaluation is termed a witnessed state appraisal, a documents that lists and precisely describes what has been detected, room by room, area by area, with utmost attention to detail, by means of overview and detail photographs, floor plans and diagrams.Once completed and signed by all the parties involved, they proceed to the oath in court and the document is deposited in the relevant files as legal evidence.

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