METHOD FOR THE INVESTIGATION OF REINFORCED CONCRETE STRUCTURES

Technical field

[01 ] The present invention relates to a method and a device for the investigation of reinforced concrete structures, in particular for the detection of the position and orientation of the elements constituting the reinforcements of such structures.

Background art

[02] In the construction sector, the need to carry out non -destructive investigations on reinforced concrete structures to verify the presence and orientation of metal reinforcements is known. These investigations are considered fundamental to allow a first evaluation of the consistency of the structure and of the mechanical resistance characteristics, as well as a first assessment of the static configuration. It should be noted that, given the seismic events that have recently affected the national territory, the need to ascertain the safety degree of the existing structures against a seismic event has increased and, in such perspective, the aforementioned investigations have become an instrument even more relevant for the technician of the sector.

[03] The technical evaluations on the reinforcements within the structural elements, such as beams, pillars, floors and lintels, are generally performed using special instruments referred to as cover meters suitable for the detection of ferromagnetic materials. Cover meters are portable instruments comprising a magnetic transducer associated with a data processing unit, designed to generate a magnetic field variable over time and directed towards the structure to be investigated. The operating principle is based on the phenomenon of magnetic induction, consisting in the fact that the magnetic field generated by the transducer induces Eddy currents on the conductive elements present in the structures, for example rods and brackets; such conductive elements, in turn, generate induced magnetic fields properly detected by the transducer. The detection of the induced magnetic fields provides information on certain characteristics of the conductive elements such as, e.g., the depth with respect to the position of the transducer, the orientation and the dimensional characteristics.

[04] An instrument of said typology is illustrated in the patent application DE 4,036,123. The patent application discloses a device for measuring the size and the position of reinforcing elements comprising a sensor, arranged within an outer casing, connected to a control unit powered by a battery. The control unit is connected by wired means to an external processing unit. The device is manually moved by the operator on the surface of the structural element so as to acquire signals revealing the presence and size of the reinforcing elements, which are processed by the external processing unit.

[05] A problem complained of in the considered sector is represented by the long time necessary to carry out the investigations, as the technician has to manually move the instrument along the entire structure to be investigated, such as a pillar, a beam or the like, to acquire the signals indicative of the presence and of the orientation of the metal reinforcements.

Presentation of the invention

[06] The task of the present invention is that of solving the above-mentioned problems, devising a method that allows to carry out the investigation of reinforced concrete structures in an optimal manner, allowing to quickly and reliably identify the presence and orientation of the elements constituting the metal reinforcements.

[07] Within this task, it is a further object of the present invention to provide a method that allows to make a more automatic investigation process.

[08] A further object of the invention is to provide a device that allows to carry out the present investigation method with ease.

[09] Another object of the invention is to provide a device that is easy to handle.

[10] Another object of the invention is to provide a device that allows to acquire and process data relating to metal reinforcements in real time.

[1 1 ] A further object of the invention is to provide a device for the investigation of reinforced concrete structures of simple constructional and functional design, provided with absolutely reliable operation, versatile in use and relatively cheap.

[12] The aforementioned objects are achieved, according to the present invention, by the method and the device for the investigation of reinforced concrete structures according to claims 1 and 5.

[13] The device for the investigation of reinforced concrete structures comprises magnetic sensor means suitable to be associated with the reinforced concrete structure to be investigated and to be operated sequentially along said reinforced concrete structure to generate a magnetic field variable over time in order to magnetize the conductive elements present in the reinforced concrete structure itself, said sensor means being suitable to detect a first datum indicative of the presence and the orientation of said conductive elements; an external control unit adapted to receive said first datum from said magnetic sensor means and to associate it with a respective second datum, indicative of the position of said magnetic sensor means along said reinforced concrete structure, so as to obtain information on the spatial configuration of said conductive elements.

[14] Preferably, said first datum and said respective second datum are transmitted to said external control unit by means of a wireless data transmission system.

[15] According to an advantageous aspect of the invention, said magnetic sensor means are movable along a parallel direction in use to said reinforced concrete structure upon command of a handling member. Preferably, said handling member carries a position sensor member suitable to detect said second datum indicating the position of said magnetic sensor means.

According to a different embodiment, said magnetic sensor means comprise a series of magnetic sensor members regularly distributed in a fixed position along a parallel direction in use to said reinforced concrete structure.

Brief Description of the Drawings

The details of the invention will become more evident from the detailed description of a preferred embodiment of the investigation device for reinforced concrete structures, illustrated by way of example in the accompanying drawings, wherein:

Figure 1 shows a longitudinal sectional view of the device for the investigation of the reinforced concrete structures according to the present invention;

Figure 2 shows a longitudinal sectional view of the device of the present invention along a plane orthogonal to the one of Figure 1 ;

Figure 3 shows a cross-sectional view of the same device;

Figures 4, 5 and 6 show corresponding views of the device for the investigation of the reinforced concrete structures in a different embodiment.

Embodiments of the invention

With particular reference to these figures, the device for the investigation of reinforced concrete structures of the present invention is referred to as 1 .

The device 1 comprises an elongated body 2 inside which magnetic sensor means 3 are housed, suitable to progressively detect, along the length of the body 2 itself, a first datum indicative of the presence and orientation of the conductive elements present in the reinforced concrete structure to be investigated, as will be better explained below.

The magnetic sensor means 3 comprise at least one magnetic sensor member 3, movable along a direction A substantially parallel to a median longitudinal axis M of the body 2.

The body 2 is preferably constituted by a hollow stem closed at the ends by suitable closure means 4. The stem 2 is sized as to be easily transportable by hand by the operator responsible for carrying out the technical investigations. Preferably, the length value of the stem LA is in the range of 1 .60 m -1 .80 m.

The closure means 4 have respective indicator buttons 5 suitable for signalling to an external control unit the measurement step of the structural element to be investigated, i.e. whether it is an initial, intermediate or final step. More in detail, the indicator buttons 5 comprise a first button 50, disposed on a first end of the stem 2, which can be actuated, preferably in contact with a surface of one end of the structural element, to signal the beginning of the measurement or rather the beginning of the first series of subsequent measurements on the structural element segment commensurate to the length L _A of the stem 2. At the second end of the stem 2, opposite the first end, a second button 51 is present, which can be actuated, preferably in contact with a surface of the opposite end of the structural element, to signal the final step of the measurement or rather the last series of subsequent measurements carried out on the structural element. The deactivation of both indicator buttons 5 signals an intermediate step comprising a series of successive measurements carried out on the structural element.

[24] On the surface of the stem 2 facing outwards a control panel 100 is present comprising a series of buttons or a touch screen allowing the user to manage the operation of the device 1 , e.g., activating and deactivating the magnetic sensor means 3 or displaying the readings of such sensor means.

[25] The magnetic sensor member 3 is arranged to generate a magnetic field variable in time in order to magnetize the conductive elements present in the reinforced concrete structural elements to be investigated and to detect a first indicative datum of the presence and orientation of the conducting elements, progressively along the length L _A of the stem 2.

[26] Preferably, the magnetic sensor member 3 continuously senses the first datum during the stroke along the stem 2.

[27] The magnetic sensor member 3 is preferably an Eddy currents sensor.

[28] Such sensor member 3 comprises at least one coil 6 of conductive material, suitably connected by electric cables 7 to an electric power supply source 8. The power supply source 8 can be constituted by a rechargeable battery associated with the stem 2.

[29] The coil 6 of conductive material performs both the function of generating a magnetic field variable in time and the function of detecting the magnetic field generated by the Eddy currents induced in the conductive elements.

[30] According to a preferred embodiment, the magnetic sensor member 3 provides a pair of coils 6 of conductive material, appropriately spaced, respectively assigned to the generation of an incident magnetic field and to the detection of the induced magnetic field.

[31 ] Each coil 6 is electrically connected to a signal processing circuit, not shown. The processing circuit is adapted to acquire and process the signals detected by the magnetic sensor member 3, as well as the signals sent by the additional sensors associated to the stem 2, such as, e.g., the indicator buttons 5.

[32] The magnetic sensor member 3 is associated with handling means 9 suitable to be actuated by an engine member 10, to shift the magnetic sensor member 3 along the direction A. The handling means 9 comprise a carriage 1 1 on which the coils 6 are mounted.

[33] The carriage 1 1 is connected to motion transmission means 12 such as for example belt or chain means which wrap around a first pulley 13, located at the first end of the stem 2 and on a second pulley 14, arranged at the opposite end of the stem 2. It is possible to provide for the first pulley 13 to be connected to the engine member 10 and the second pulley 14 to be idle. Alternatively, both the pulleys 13, 14 are idle and a third motorized pulley 15 is interposed between the first pulley 13 and the second pulley 14 to operate in motion the transmission means 12.

[34] A position sensor, of the type, e.g., known as an encoder, is associated with the engine member 10, suitable to detect, preferably continuously, a second datum indicative of the position of the magnetic sensor member 3.

[35] The first datum, indicative of the presence and orientation of the conducting elements, and the second datum, indicative of the position of the magnetic sensor member 3, are sent through a wireless transmission system to the external control unit, not shown, suitable for receiving the data and for associating each first datum with a respective second datum in order to obtain information on the spatial configuration of the conductive elements present in the investigated structural element.

[36] The wireless data transmission system includes a data transmission board, installed on the stem 2 and not visible in the figures. The data transmission board is Bluetooth and/or Wi-Fi.

[37] The control unit external to the stem 2 can be a PC, e.g., a portable PC. The external control unit comprises a central processing unit connected to a screen to display the processed data. The data are processed according to a specific calculation program that allows to display on the screen the information related to the spatial arrangement of the conductive elements. Such information is preferably presented on the screen as a three- dimensional graphic representation of the metal reinforcement of the investigated structural element.

[38] An orientation sensor member 16 is associated with the stem 2 adapted to measure the inclination of the stem 2 to allow the stem 2 itself to be arranged substantially aligned with respect to a horizontal or vertical measurement direction with respect to the ground. Preferably, the orientation sensor member 16 is a gyroscope.

[39] The method for the investigation of reinforced concrete structures according to the present invention provides first of all to arrange the device 1 at one end of the structural element to be investigated which may be, by way of example, a beam or a pillar.

[40] In particular, the first end of the stem 2 is arranged at one end of the structural element to be investigated. For example, in the case of a pillar, the end of the stem 2 is resting on the ground, near the pillar.

[41 ] Then, the first button 50 is activated, sending a signal suitable for indicating the start step of the measurement of the structural element to the external control unit.

[42] Preferably, the step of activating the first button 50 provides for pressing the button 50 against the end surface of the structural member or a surface near such end.

The device 1 is then aligned according to a measuring direction substantially horizontal or vertical with respect to the ground by the use of the orientation sensor member 16.

Once the device 1 is correctly oriented, the magnetic sensor means 3 are actuated. The step of operating the magnetic sensor means 3 provides, in particular, for driving the magnetic sensor member 3 along the direction A in translational motion. The moving action of the magnetic sensor member 3 is carried out, e.g., by means of the use of the control panel 100 so as to send the command signal to the engine member 10.

Subsequently, a first datum indicating the presence and orientation of the conductive elements in the structural element to be investigated is progressively detected along the length L _A of the stem 2.

The step also provides for progressively detecting a second datum along the length L _A of the stem 2, indicative of the position of the magnetic sensor member 3 through the position sensor.

The method then provides for transmitting each first datum and each second datum to the external control unit and to associate each first datum, indicative of the presence and orientation of the conductive elements, with a respective second datum, indicative of the position of the magnetic sensor member 3, so as to obtain information on the spatial configuration of the conductive elements present in the investigated structural element. Preferably, the transmission of each first datum and of each second datum to the external control unit is carried out by means of the wireless transmission system.

The method advantageously provides for displaying in real time, on the screen of the external control unit, information on the spatial configuration of the conductive elements, preferably as a three-dimensional graphic representation of the conductive elements. In this way a three-dimensional representation of the metal reinforcements of the structural element to be investigated is obtained.

In the case wherein the length of the structural element to be investigated is substantially equal to the length L _A of the stem 2, the shifting of the magnetic sensor member 3 is arrested by the external control unit when the magnetic sensor member 3 reaches the end of the stroke along the stem 2. The investigation of the structural element is therefore considered finished.

In the case in which the length of the structural element to be investigated is greater than the length L _A of the stem 2, the stem 2 is moved along the measurement direction so as to repeat the above steps and thus allowing to carry out the readings of the first datum and of the second datum on the entire length of the structural element.

If the length of the structural element is less than or equal to twice the length L _A of the stem 2, the step of moving the stem 2 along the measurement direction provides for abutting the second end of the stem 2 on the end of the structural element opposite the beginning of the measurement.

The first button 50 is then deactivated and the second button 51 is activated, which sends to the external control unit a signal suitable for indicating the final step of the measurement of the structural element.

Preferably, the second button 51 is activated by pressing such button against the end surface of the structural element.

Then, the above steps are repeated to align the device 1 along the measurement direction, to operate the magnetic sensor member 3 in translational motion and transmit each acquired first datum and each acquired second datum to the external control unit. If, on the other hand, the length of the structural element is greater than twice the length L _A of the stem 2, the step of moving the stem 2 along the measurement direction provides for positioning the first end of the stem 2 at the position, previously occupied by the second end of the stem 2.

In this step, the first button 50 is deactivated and the second button 51 is not activated. The deactivation of both indicator buttons 5 results in sending a signal to the external control unit, indicating an intermediate measurement step.

The aforementioned steps are then repeated for the acquisition of the values of the first datum and of second datum on the segment of the investigated structural element.

The step of moving the stem 2 along the measuring direction is repeated a number of times necessary to cover the entire length of the structural element. Before making the last series of measurements, the second button 51 is activated to signal the final measurement step.

It should be noted that, in the case wherein the length of the structural element is not a multiple of the length L _A of the stem 2, at least one overlapping portion of the readings is present, wherein the readings are carried out twice.

Therefore, before arranging the device 1 for carrying out the initial measurement step, dimensional data relative to the structural element to be investigated are provided to the external control unit so that, given the length L _A of the stem 2, the control unit could detect the overlapping segment and possibly use the second reading as a control on the first conducted reading.

Figures 4, 5 and 6 show a different embodiment of the invention wherein the device provides a series of magnetic sensor members 3 distributed along the direction A; the magnetic sensor members 3 occupy fixed positions along such direction A.

In particular, each magnetic sensor member 3 comprises at least one coil 6 of conductive material. Therefore, multiple coils 6 of conductive material are regularly distributed along the direction A. [64] Preferably the coils 6 are arranged in substantially parallel rows and are positioned, for each row, at a predetermined distance from each other. In the illustrated case, the coils 6 are arranged according to two parallel rows, but it is possible to provide a different number of rows. The coils 6 are mutually offset with respect to the median longitudinal axis M of the stem 2.

[65] Preferably the coils 6 are mounted inside the stem 2 with the symmetric axis S orthogonal to the median longitudinal axis M.

[66] The coils 6 are powered by the electrical energy source 8 which is associated with an internal electronic control unit 17 comprising the processing circuit of the signals detected by the coils 6.

[67] The internal electronic control unit 17 is suitable to individually activate the coils 6, according to a predetermined sequence in order to generate a magnetic field variable over time to magnetize the conductive elements present in the structural elements to be investigated.

[68] Preferably, the internal control unit 17 activates the coils 6 in sequence along the length L _A of the stem 2.

[69] The coils 6 progressively detect, along the length L _A of the stem 2, a first datum indicating the presence and orientation of the conductive elements present in the reinforced concrete structure to be investigated.

[70] The first datum, indicative of the presence and orientation of the conductive elements, and the second datum, indicative of the position of the individual coils 6, are sent through the wireless transmission system to the external control unit.

[71 ] Shielding means 18 suitable to avoid the occurrence of interference phenomena between the magnetic fields generated by the coils 6, are arranged between the first row and the second row of coils 6.

[72] The shielding means 18 preferably extend along the median longitudinal axis M and comprise a separation baffle which extends along the entire length of the stem 2, made of a material suitable to operate as a magnetic shield.

[73] Preferably the shielding means 18 are made of MuMETAL®.

[74] In the case of using the aforesaid embodiment, the step of operating the magnetic sensor means 3 provides for individually activating, according to a predetermined sequence, the coils 6 of conductive material by means of the internal electronic control unit 17.

[75] The next step of progressively detecting the first datum along the entire length L _A of the stem 2 is made by means of the coils 6 of conductive material distributed along the stem 2 and the second datum detected in this step is relative to the occupied position by the coils 6 along the stem.

[76] The internal electronic control unit 17 controls the activation or deactivation of the coils 6; therefore, if the external control unit receives a signal from the indicator buttons 5 indicating the final measurement step, the unit 17 deactivates the coils 6 once the series of successive measurements along the stem 2 has finished.

It is possible to provide that the stem 2 is of a telescopic type so as to allow the length of the device 1 to be extended and to make it more adaptable to the dimensional characteristics of the structural elements to be investigated. The stem 2 is formed by an outer casing comprising an inner casing coaxial to the outer casing and extractable from the outer casing. The coils 6 are mounted in the inner casing, or the carriage 1 1 which carries the at least one coil 6 is slidable in the inner casing.

The described method achieves the aim of quickly and reliably detecting the presence and orientation of the conductive elements constituting the metal reinforcements.

In fact, it is sufficient to arrange the stem and operate the magnetic sensor means to acquire along the length of the stem a first datum relating to the presence and orientation of the conductive elements, which, associated with a second datum indicating the position of the sensor means, allows the external control unit to obtain information on the metal reinforcement and to process a graphic representation of the metal reinforcement itself. The user is therefore not forced to manually move the magnetic sensor means for the entire length of the structural element to be investigated but simply uses the stem and the control panel, and, if required, moves the stem to cover the full length of the structural element.

Advantageously, the use of a telescopic stem further facilitates the user in the investigation as it is possible to more easily adapt the length of the stem to the length of the structural element.

It should be noted that the method of investigation is made more automatic considering that the user only has to arrange the stem in the measurement direction and to operate the magnetic sensor means. The external control unit processes the acquired data continuously and identifies any overlapping segments of the readings, without requiring the intervention of the user.

It should also be noted that the device for the investigation of reinforced concrete structures is easily transportable since it comprises a small stem and an external control unit which could be a portable computer. The absence of electric cables connecting the device to the external control unit, thanks to the wireless data transmission mode, helps to make the device easy to handle for the user.

A prerogative of the device is also the fact that the external control unit processes data in real time allowing to display the information related to the spatial configuration of the elements of the reinforcements in real time. In particular, the external control unit advantageously allows to display on the screen, in real time, a three-dimensional graphic representation of the metal reinforcement of the investigated structural element.

[84] Therefore, the user can have a first view of the structural characteristics of the investigated element and then, later on, use the data stored in the archive of the control unit for an in-depth study of the structure.

[85] The device, disclosed by a way of example, is susceptible of several modifications and variations depending on the different requirements.

[86] In the practical embodiment of the invention, the materials used, as well as shape and dimensions, may be any according to requirements.

[87] Where the technical features mentioned in any of the claims are followed by reference numerals, these reference numerals are included to improve the comprehension of the claims only, and consequently they have no limiting effect on the object of each element identified by way of example by these reference numerals.