{"id":8540,"date":"2026-10-04T14:18:58","date_gmt":"2026-10-04T13:18:58","guid":{"rendered":"https:\/\/guemisa.es\/?post_type=casos-de-uso&#038;p=8540"},"modified":"2026-10-04T14:18:59","modified_gmt":"2026-10-04T13:18:59","slug":"monitoring-bridges-laser-sensors","status":"publish","type":"casos-de-uso","link":"https:\/\/guemisa.es\/en\/casos-de-uso\/monitorizacion-puentes-sensores-laser\/","title":{"rendered":"Bridge monitoring with laser sensors: deflection, deformation and displacement"},"content":{"rendered":"<p>The <strong>bridge monitoring with laser distance sensors<\/strong> It allows continuous and non-contact measurement of changes in position, deflection, deformation and relative displacements in boards, piles, supports, pylons and other structural elements.<\/p>\n<p>In applications of <strong>bridge inspection<\/strong>, For load testing or monitoring during rehabilitation work, a laser sensor can be installed on a stable reference point and repeatedly measure the distance to a point on the structure. The evolution of this distance allows for the detection of millimeter-level movements and analysis of how the bridge responds to loads, traffic, assembly operations, thermal changes, or construction work.<\/p>\n<p>The measurement is conceptually simple, but its correct interpretation requires studying the installation geometry. A laser sensor directly measures a <strong>distance<\/strong>; Converting that distance into a vertical arrow, horizontal displacement, or structural deformation requires knowing the position of the sensor, the target, and the possible directions of movement.<\/p>\n<p>This application is part of our guide on <a href=\"https:\/\/guemisa.es\/en\/use-cases\/monitoring-bridges-pillars-tunnels-slopes\/\">monitoring of structures, bridges, tunnels and slopes with laser sensors<\/a>.<\/p>\n<p><!-- IMAGEN 1: imagen principal \/ esquema general de monitorizaci\u00f3n de un puente --><\/p>\n<h2>What can be measured on a bridge with a laser sensor?<\/h2>\n<p>A <strong>laser distance sensor<\/strong> It measures the distance between the instrument and the point or target on which the beam is directed. Depending on how the installation is designed, this measurement can be used to monitor different structural phenomena.<\/p>\n<ul>\n<li><strong>Dashboard arrow or deflection:<\/strong> vertical displacement of one or more points of the deck when loads, traffic or vehicles used during a load test are acting.<\/li>\n<li><strong>Stack displacement:<\/strong> control of movements with respect to a reference considered stable.<\/li>\n<li><strong>Support movement:<\/strong> monitoring of relative changes between elements of the structure.<\/li>\n<li><strong>Movement between pylon and board:<\/strong> long-distance measurement of geometric variations between different parts of the bridge.<\/li>\n<li><strong>Deformation of metallic structures:<\/strong> multi-point tracking during transport, lifting, assembly or positioning.<\/li>\n<li><strong>Behavior during rehabilitation:<\/strong> detection of movements while cutting, dismantling or modifying elements of an existing structure.<\/li>\n<li><strong>Response to loads:<\/strong> recording of displacement curves during static or dynamic load tests.<\/li>\n<\/ul>\n<p>A single sensor provides a <strong>scalar distance<\/strong>. Therefore, it does not directly measure mechanical stress, load-bearing capacity, or a complete three-dimensional displacement. When it is necessary to know several components of the motion, several sensors, other measurement directions, or complementary instruments can be used.<\/p>\n<h2>Measuring the deflection of a bridge with laser sensors<\/h2>\n<p>The <strong>arrow of a bridge<\/strong> This is one of the most interesting applications of non-contact laser measurement. The goal is to observe how much a point on the board moves vertically relative to a reference point during the application of a load or over time.<\/p>\n<h3>Approximately vertical measurement<\/h3>\n<p>The simplest arrangement involves installing the sensor on a stable reference point located below the structure and directing the beam towards the point on the board whose arrow is to be measured.<\/p>\n<p>If the direction of the laser practically coincides with the direction of movement, the measured distance variation can be directly related to the displacement of the board.<\/p>\n<p><!-- IMAGEN 2: esquema sensor vertical bajo tablero para medici\u00f3n de flecha --><\/p>\n<p>This configuration can be particularly interesting in <strong>bridge load tests<\/strong>, because it allows the measurement to be taken without physically attaching a transducer to the board.<\/p>\n<h3>Measurement using an oblique line of sight<\/h3>\n<p>It is not always possible to place the sensor directly under the point of interest. In many structures, access, traffic, a waterway, a railway line, or the bridge&#039;s geometry itself necessitate taking measurements from an inclined line of sight.<\/p>\n<p>In a simplified scheme, if <strong>x<\/strong> represents the horizontal separation, <strong>z<\/strong> the vertical separation and <strong>L<\/strong> the distance measured by the sensor:<\/p>\n<p><strong>L\u00b2 = x\u00b2 + z\u00b2<\/strong><\/p>\n<p>If only the vertical component changes and the horizontal component remains constant, for small displacements it can be approximated as follows:<\/p>\n<p><strong>\u0394z \u2248 \u0394L \/ sin \u03b8<\/strong><\/p>\n<p>where <strong>\u03b8<\/strong> It is the angle of the line of sight with respect to the horizontal.<\/p>\n<p><!-- IMAGEN 3: esquema geom\u00e9trico de visual oblicua con L, x, z y theta --><\/p>\n<p>This geometry is important: a nearly horizontal line of sight has little sensitivity to vertical movement. Furthermore, if the measurement point and the reference point move simultaneously, a single distance is insufficient to separate the two components.<\/p>\n<p>Therefore, before selecting the sensor, it must be defined <strong>what movement is to be measured, in what direction it occurs, and what elements can be displaced<\/strong>.<\/p>\n<h2>Bridge load testing: a contactless alternative to an LVDT<\/h2>\n<p>The <strong>bridge load tests<\/strong> They allow comparison of the actual behavior of the structure with that predicted by the calculation model. One of the magnitudes that can be recorded is the deflection produced when known loads are moved or positioned on the deck.<\/p>\n<p>Displacement transducers such as LVDTs can traditionally be installed on structures, tripods, scaffolding, or reference points located beneath the bridge. In certain locations, this installation can be complicated, especially over railway lines, roads, waterways, or areas with difficult access.<\/p>\n<p>An alternative solution is to use <strong>laser distance sensors installed from a reference located outside the structure<\/strong>.<\/p>\n<h3>Documented case: load test on a railway line<\/h3>\n<p>In a test conducted in collaboration with engineering <strong>AECOM<\/strong> On a bridge located over commuter rail lines in New England, four Dimetix laser sensors were used to measure the deflection of different points on the deck.<\/p>\n<p>The structure showed signs of deterioration and its load limit had previously been reduced. The objective of the test was to determine its actual behavior and compare it with the structural model.<\/p>\n<p>To avoid the conventional installation of LVDTs on tripods and auxiliary structures, the following were used: <strong>four Dimetrix DAN-10-150 sensors<\/strong>. Each sensor was installed on an independent support fixed to the ballast under the bridge and oriented towards a specific point on the structure.<\/p>\n<p>The sensors were connected to interface modules and the acquisition system used during the test. The four deflection signals were recorded in real time while different passes were made with loaded vehicles.<\/p>\n<p><!-- IMAGEN 4: sensor l\u00e1ser bajo puente \/ esquema prueba de carga --><\/p>\n<p>The loads were progressively increased, and the corresponding deflection curves were recorded. The measurements showed repeatable behavior, and the deflections returned to their initial position after the load was removed.<\/p>\n<p>The displacement and deformation results obtained during the test were consistent with the model predicted by AECOM. The test allowed for a reassessment of the structure&#039;s behavior and a subsequent increase in its load rating.<\/p>\n<p>This example demonstrates an important advantage of optical measurement: <strong>The instrumentation can be located outside the structural element being tested.<\/strong>, reducing the need to install contact sensors directly on the dashboard.<\/p>\n<h2>Real case 1: monitoring of the Huey P. Long Bridge during lifting<\/h2>\n<p>One of the most representative bridge monitoring projects using Dimetix sensors was carried out during the expansion of the <strong>Huey P. Long Bridge over the Mississippi River, in New Orleans<\/strong>.<\/p>\n<p>The project included two enormous sections of steel lattice initially built on land. Each section was approximately <strong>528 feet long, about 161 meters, and a weight close to 2,700 tons<\/strong>.<\/p>\n<p>The structures were transported on barges to the bridge and subsequently lifted approximately <strong>130 feet, about 40 meters<\/strong>, until its final position.<\/p>\n<p><!-- IMAGEN 5: Huey P. Long Bridge \/ izado de la celos\u00eda --><\/p>\n<h3>The problem: controlling deformation during a critical maneuver<\/h3>\n<p>During transport, lifting and positioning there was a risk that a structure of these dimensions would experience out-of-plane deformations, excessive stresses or even buckling phenomena.<\/p>\n<p>The responsible engineering team needed to know in real time how the geometry of the lattices was changing in order to be able to act during the maneuver.<\/p>\n<h3>Ten laser sensors working simultaneously<\/h3>\n<p>A total of <strong>10 Dimetix laser distance sensors, five installed on each lattice<\/strong>. The historical equipment used in this project belonged to the previous DLS-C generation.<\/p>\n<p>Each set of five sensors allowed for monitoring different points and observing out-of-plane deformations of the structure.<\/p>\n<p>The sensors were connected by cable to a data logger. The information was sent to a computer located under the deck, where the project managers could graphically visualize the tilt and deformation of the structures.<\/p>\n<p>The system updated the information approximately <strong>every five seconds<\/strong>.<\/p>\n<p><!-- IMAGEN 6: esquema de celos\u00eda con 5 sensores \/ sensor instalado --><\/p>\n<h3>Corrections during the lifting process itself<\/h3>\n<p>The information was not used solely for later record-keeping. Engineers could observe the structure&#039;s evolution during operation and make adjustments. <strong>on-the-fly corrections to the lattice position<\/strong> without stopping the process.<\/p>\n<p>Monitoring also continued during the final lateral displacement of the structures to their position on the supports, a phase considered equally critical.<\/p>\n<p><strong>Technical conclusion:<\/strong> This case demonstrates why, in large structures, monitoring multiple points simultaneously can be more useful than a single distance. Comparing multiple sensors allows for the observation of geometric changes that a single measurement point could not identify.<\/p>\n<h2>Real case 2: monitoring Vienna&#039;s A23 during its reconstruction<\/h2>\n<p>Another example of an application is the <strong>Vienna A23 motorway<\/strong>, an infrastructure with high traffic intensity.<\/p>\n<p>The project affected two bridges belonging to a section originally built around 1970. During the remodeling of the A23, the existing structures had to be dismantled and rebuilt.<\/p>\n<p>The project documentation indicates an approximate intensity of <strong>180,000 vehicles daily<\/strong>.<\/p>\n<p><!-- IMAGEN 7: puente A23 Viena \/ plano de sensores --><\/p>\n<h3>Controlling movements during the work<\/h3>\n<p>One of the concerns during the intervention was the possibility that the vertical elements or supports might experience displacements due to the modifications made to the structure.<\/p>\n<p>They were installed <strong>Dimetix laser sensors oriented towards measurement targets<\/strong> to control stability as the construction phases progressed.<\/p>\n<p>During particularly critical operations, such as cutting parts of the existing structure, distances could be continuously recorded to identify movements or geometric changes from their earliest stages.<\/p>\n<h3>A particularly interesting application for bridge rehabilitation<\/h3>\n<p>In rehabilitation work it can be very difficult to predict exactly how an existing structure will respond when pavements, load-bearing elements, temporary supports or parts of the deck are removed.<\/p>\n<p>Monitoring allows us to relate the observed changes to specific moments in the construction:<\/p>\n<ul>\n<li>cutting or demolition of elements;<\/li>\n<li>removal of material;<\/li>\n<li>entrance of heavy machinery;<\/li>\n<li>support changes;<\/li>\n<li>tightened or loosened;<\/li>\n<li>placement of new elements;<\/li>\n<li>thermal variations;<\/li>\n<li>traffic or load changes.<\/li>\n<\/ul>\n<p>For this reason, in a <strong>auscultation during works<\/strong> Simply storing a series of distances is not enough. It is advisable to also record the date and time of key construction events in order to later link them to the structural evolution.<\/p>\n<h2>Real case 3: More than 100 meters between a pylon and the deck of a bridge in Thailand<\/h2>\n<p>The ability to work at long distances allows the use of laser sensors in geometries that would be difficult to instrument using contact transducers.<\/p>\n<p>On a bridge over the <strong>Chao Phraya River, in Thailand<\/strong>, A Dimetix sensor was installed on top of a pylon and oriented towards a <strong>reflective sheet located approximately in the center of the bridge<\/strong>.<\/p>\n<p>The separation between the pylons was approximately <strong>200 meters<\/strong> and the distance measured by the sensor exceeded <strong>100 meters<\/strong>.<\/p>\n<p><!-- IMAGEN 8: puente Tailandia + esquema pilono a reflector central --><\/p>\n<h3>Millimeter-precise measurement over long distances<\/h3>\n<p>The application documents a measurement accuracy of <strong>\u00b11 mm<\/strong> and a repeatability of <strong>\u00b10.3 mm<\/strong>.<\/p>\n<p>In this type of installation, the use of a reflective sheet allows for a significant increase in the usable distance and provides a clearly defined optical target.<\/p>\n<p>But there is another parameter that must be considered: <strong>The size of the laser dot increases with distance<\/strong>.<\/p>\n<p>In the Dimetix sensors of this family, the declared spot at 100 meters is approximately <strong>55 \u00d7 30 mm<\/strong>. The reflector must be sized taking into account not only the beam size, but also:<\/p>\n<ul>\n<li>the expected movement of the board;<\/li>\n<li>the possible transverse movement;<\/li>\n<li>alignment tolerances;<\/li>\n<li>the thermal expansion of the structure;<\/li>\n<li>vibrations;<\/li>\n<li>the movements of the pylon itself;<\/li>\n<li>the margin needed to avoid missing the target.<\/li>\n<\/ul>\n<h3>Measuring distance does not mean directly measuring the vertical arrow.<\/h3>\n<p>This example is especially useful for understanding the geometry of a monitoring system.<\/p>\n<p>The sensor measures the <strong>relative distance between the pylon and the point on the board<\/strong>. If both elements can move and the view is oblique, any recorded variation may contain different components of the movement.<\/p>\n<p>Therefore, the data interpretation must be performed according to the geometric model of the bridge. If it is necessary to separate different components, additional sensors or other instrumentation techniques may be required.<\/p>\n<h2>Which Dimetix sensor can currently be used?<\/h2>\n<p>Existing projects can utilize Dimetix models from previous generations. For new installations, the current sensor should be selected based on distance, target, speed, required accuracy, communications, and environmental conditions.<\/p>\n<p>For long-range applications, one of the models that can be considered is the <a href=\"https:\/\/guemisa.es\/en\/products\/laser-sensor-dpe-10-500-dimetix\/\"><strong>Dimetrix DPE-10-500<\/strong><\/a>.<\/p>\n<table>\n<thead>\n<tr>\n<th>Feature<\/th>\n<th>Dimetrix DPE-10-500<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Range on natural surfaces<\/td>\n<td>0.05 m to approximately 100 m<\/td>\n<\/tr>\n<tr>\n<td>Range with reflective sheeting<\/td>\n<td>Approximately 0.5 to 500 m<\/td>\n<\/tr>\n<tr>\n<td>Typical accuracy<\/td>\n<td>\u00b11 mm to \u00b12\u03c3<\/td>\n<\/tr>\n<tr>\n<td>Typical repeatability<\/td>\n<td>\u00b10.3 mm at \u00b12\u03c3<\/td>\n<\/tr>\n<tr>\n<td>Maximum measurement frequency<\/td>\n<td>250 Hz<\/td>\n<\/tr>\n<tr>\n<td>Maximum output frequency<\/td>\n<td>1 kHz<\/td>\n<\/tr>\n<tr>\n<td>Operating temperature<\/td>\n<td>-40 to +60 \u00b0C<\/td>\n<\/tr>\n<tr>\n<td>Protection<\/td>\n<td>IP65<\/td>\n<\/tr>\n<tr>\n<td>Interfaces<\/td>\n<td>RS-232, RS-422\/RS-485, SSI, 0\/4\u201320 mA and Industrial Ethernet options<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Output frequency and measurement frequency are different concepts: having an output of up to 1 kHz does not mean obtaining 1,000 new independent measurements per second. The maximum declared measurement frequency of the DPE-10-500 is 250 Hz.<\/p>\n<p>For shorter distances or projects with other economic and technical requirements, there are different versions within the <a href=\"https:\/\/guemisa.es\/en\/category\/laser-distance-sensor\/\">range of laser distance sensors<\/a>.<\/p>\n<h2>How to design a laser monitoring installation on a bridge<\/h2>\n<h3>1. Define exactly what you want to measure<\/h3>\n<p>Before selecting a sensor, the magnitude to be monitored must be established:<\/p>\n<ul>\n<li>vertical arrow;<\/li>\n<li>longitudinal movement;<\/li>\n<li>transverse movement;<\/li>\n<li>stack displacement;<\/li>\n<li>relative motion between two elements;<\/li>\n<li>deformation during a maneuver;<\/li>\n<li>response during a load test.<\/li>\n<\/ul>\n<h3>2. Choose a stable reference<\/h3>\n<p>A sensor measures the distance between two points. If the sensor mount is moved, the system can interpret that movement as belonging to the bridge.<\/p>\n<p>The stability of the reference is therefore as important as the accuracy of the sensor itself.<\/p>\n<h3>3. Analyze the geometry<\/h3>\n<p>The beam direction must be compatible with the motion component that is intended to be observed.<\/p>\n<p>A vertical view can simplify a deflection measurement. An oblique view can be perfectly valid, but it requires a geometric transformation and knowledge of which other components may vary.<\/p>\n<h3>4. Select natural surface or reflector<\/h3>\n<p>At moderate distances, it may be possible to measure directly on a suitable natural surface. When the distance increases or a clearly defined target is needed, it may be advisable to install a compatible reflective sheet.<\/p>\n<p>The size of the target must incorporate sufficient margin for the beam diameter and the anticipated movements.<\/p>\n<h3>5. Design the supports correctly<\/h3>\n<p>The supports should minimize:<\/p>\n<ul>\n<li>vibrations;<\/li>\n<li>own movements;<\/li>\n<li>uncontrolled thermal expansion;<\/li>\n<li>changes in orientation;<\/li>\n<li>accidental misalignments.<\/li>\n<\/ul>\n<h3>6. Protect the optical path<\/h3>\n<p>Outdoors, rain, fog, dust, snow, condensation, solar radiation, and dirt should be taken into account.<\/p>\n<p>The IP rating of the sensor protects the equipment, but does not in itself guarantee that the <strong>optical path<\/strong> always remain available.<\/p>\n<p>If the sensor is placed behind a protective window, the material, inclination, reflections and possible soiling should also be evaluated.<\/p>\n<h3>7. Also record the quality of the measurement<\/h3>\n<p>Structural monitoring should not only store a distance number. When the system architecture allows, it is advisable to record:<\/p>\n<ul>\n<li>measured value;<\/li>\n<li>date and time;<\/li>\n<li>valid or invalid reading status;<\/li>\n<li>communication events;<\/li>\n<li>available signal strength or quality;<\/li>\n<li>temperature;<\/li>\n<li>relevant construction or loading events.<\/li>\n<\/ul>\n<h3>8. Establish a baseline<\/h3>\n<p>Before interpreting the movements, the initial behavior of the system must be recorded and its repeatability checked.<\/p>\n<p>A functional test with known displacements helps to verify the relationship between the sensor reading and the expected actual movement.<\/p>\n<h2>Laser sensor versus LVDT, total station, GNSS and inclinometer<\/h2>\n<p>There is no single instrument suitable for all auscultation applications. Different technologies can be complementary.<\/p>\n<table>\n<thead>\n<tr>\n<th>Technology<\/th>\n<th>What does it primarily measure?<\/th>\n<th>Key advantage<\/th>\n<th>Aspect to consider<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>Laser distance sensor<\/strong><\/td>\n<td>Distance between sensor and target<\/td>\n<td>Continuous, contactless, and long-distance measurement<\/td>\n<td>It requires line of sight and a properly defined geometry.<\/td>\n<\/tr>\n<tr>\n<td><strong>LVDT<\/strong><\/td>\n<td>Local linear displacement<\/td>\n<td>Very suitable for short relative distance travel<\/td>\n<td>Requires contact and a nearby mechanical reference<\/td>\n<\/tr>\n<tr>\n<td><strong>Total station<\/strong><\/td>\n<td>Target coordinates<\/td>\n<td>It allows you to control multiple points in a coordinate system<\/td>\n<td>The frequency and complexity of the system are different from a dedicated measure.<\/td>\n<\/tr>\n<tr>\n<td><strong>GNSS<\/strong><\/td>\n<td>Absolute or relative position<\/td>\n<td>Interesting in large structures and global movements<\/td>\n<td>It requires suitable satellite reception conditions<\/td>\n<\/tr>\n<tr>\n<td><strong>Inclinometer<\/strong><\/td>\n<td>Angle or angular variation<\/td>\n<td>Very useful for controlling rotation and tilt<\/td>\n<td>It does not directly measure a linear displacement.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>In a system of <strong>Structural Health Monitoring (SHM)<\/strong> Several technologies can be combined. For example, a laser sensor can monitor displacement, an inclinometer can record rotations, and temperature sensors can help interpret thermally based movements.<\/p>\n<h2>Advantages of laser sensors for bridge inspection<\/h2>\n<ul>\n<li><strong>Non-contact measurement:<\/strong> It is not necessary to mechanically attach the sensor to the moving point.<\/li>\n<li><strong>Large working distance:<\/strong> Certain models allow working at tens or hundreds of meters.<\/li>\n<li><strong>Millimeter precision:<\/strong> Suitable for numerous structural displacement applications.<\/li>\n<li><strong>High acquisition frequency:<\/strong> It allows for the study of phenomena that are faster than with manual reading systems.<\/li>\n<li><strong>Industrial integration:<\/strong> Availability of serial, analog and industrial network interfaces depending on the model.<\/li>\n<li><strong>Remote installation:<\/strong> The sensor can be placed outside of hard-to-reach areas.<\/li>\n<li><strong>Permanent or temporary monitoring:<\/strong> It can be used both during a test and in continuous monitoring facilities.<\/li>\n<li><strong>Multipoint measurement:<\/strong> Multiple sensors can simultaneously monitor different positions of a structure.<\/li>\n<\/ul>\n<h2>Limitations that must be considered<\/h2>\n<p>The laser sensor does not eliminate the need to properly design the auscultation system.<\/p>\n<ul>\n<li>A proper line of sight must be maintained.<\/li>\n<li>The stability of the support is part of the overall uncertainty.<\/li>\n<li>The surface of the target influences the range.<\/li>\n<li>Rain, fog, dirt, or condensation may affect the availability of the measurement.<\/li>\n<li>An oblique view requires geometric interpretation.<\/li>\n<li>The accuracy indicated in the sensor&#039;s technical data sheet does not automatically equate to the uncertainty of the entire installation.<\/li>\n<li>Thermal movements of the structure must be differentiated from other displacements when relevant.<\/li>\n<\/ul>\n<h2>Frequently asked questions about bridge monitoring with laser sensors<\/h2>\n<h3>Can a laser sensor directly measure the deflection of a bridge?<\/h3>\n<p>Yes, provided the installation geometry allows relating the distance variation to the vertical displacement of the observed point. An approximately vertical installation simplifies this relationship. In an oblique view, the corresponding geometry must be applied.<\/p>\n<h3>Can a laser sensor be used in a load test?<\/h3>\n<p>Yes. There are documented applications where Dimetix sensors have recorded in real time the deflection of different points of the deck while known loads were applied to the bridge.<\/p>\n<h3>Can it replace an LVDT?<\/h3>\n<p>In certain applications, the installation of an LVDT can be avoided, especially when non-contact measurement is desired or when it is difficult to place a mechanical reference near the measurement point. These technologies are not equivalent in all cases, and the choice should be made according to the geometry, travel distance, accuracy, and dynamics of the test.<\/p>\n<h3>What distance can be measured?<\/h3>\n<p>It depends on the model and the surface. For example, the Dimetix DPE-10-500 claims approximately 100 meters on natural surfaces and up to 500 meters using reflective sheeting under suitable conditions.<\/p>\n<h3>Can a bridge be measured from more than 100 meters away?<\/h3>\n<p>Yes. There is a documented application in Thailand where the sensor works at a distance of more than 100 meters between a pylon and a reflector installed on the dashboard.<\/p>\n<h3>Is a reflective sheet necessary?<\/h3>\n<p>Not always. At shorter distances, it may be possible to measure directly on the surface of the structure. For long distances, problematic surfaces, or when a well-defined optical reference point is required, using a reflector may be advisable.<\/p>\n<h3>Does an accuracy of \u00b11 mm mean that the entire installation has an uncertainty of \u00b11 mm?<\/h3>\n<p>No. Overall uncertainty also depends on the mounting, reference stability, geometry, target, environment, data acquisition, and processing. Sensor accuracy is only one part of the measurement system.<\/p>\n<h3>Can it be permanently installed outdoors?<\/h3>\n<p>Suitable models can be used in outdoor applications, but the protection of the assembly and the optical path against water, condensation, dust, dirt and other environmental factors must be studied.<\/p>\n<h3>Can it be used to monitor batteries and supports during rehabilitation?<\/h3>\n<p>Yes. Monitoring distances between predefined references allows for the detection of relative displacements during demolition, cutting, reconstruction, support changes, or other operations.<\/p>\n<h3>Can a single sensor determine movement in X, Y, and Z?<\/h3>\n<p>No. A laser sensor provides a distance measurement in the direction of its beam. To separate different components of motion, a geometry with multiple observations, multiple sensors, or additional instrumentation is needed.<\/p>\n<h2>Selecting the solution for each bridge<\/h2>\n<p>The choice of sensor should be based on the application and not solely on the maximum distance indicated in the catalog.<\/p>\n<p>To study an installation, we need to know, at a minimum:<\/p>\n<ul>\n<li>approximate distance between sensor and target;<\/li>\n<li>maximum expected movement;<\/li>\n<li>direction of displacement;<\/li>\n<li>precision required;<\/li>\n<li>required measurement frequency;<\/li>\n<li>type of surface or available target;<\/li>\n<li>environmental conditions;<\/li>\n<li>assembly possibilities;<\/li>\n<li>type of recorder, PLC or acquisition system;<\/li>\n<li>required communication interfaces.<\/li>\n<\/ul>\n<p>A simple sketch indicating the point where the sensor can be installed, the objective and the intended direction of movement is usually sufficient to carry out an initial feasibility assessment.<\/p>\n<h2>Technical sources of the cases described<\/h2>\n<p>The real-world examples included on this page have been compiled from published technical documentation on actual installations:<\/p>\n<ul>\n<li><strong>Dimetix Application Example AE-0510:<\/strong> structural monitoring during the transport, lifting and positioning of the Huey P. Long Bridge trusses.<\/li>\n<li><strong>Dimetix Application Example AE-0703:<\/strong> Monitoring of A23 motorway bridges during reconstruction work in Vienna.<\/li>\n<li><strong>Dimetix Application Example AE-0704:<\/strong> monitoring at more than 100 meters between pylon and deck on a bridge over the Chao Phraya River, Thailand.<\/li>\n<li><strong>Application documented by Laser-View Technologies in conjunction with AECOM:<\/strong> Deflection measurement during a load test using four Dimetix DAN-10-150 sensors.<\/li>\n<\/ul>\n<p>Models used in historical projects may correspond to previous generations. Selection for a current installation should be made using the current specifications of the available model.<\/p>\n<h2>Check your bridge monitoring application with GUEMISA<\/h2>\n<p>In <strong>GUEMISA<\/strong> We can help you select the Dimetix laser sensor and study the basic measurement geometry for applications of <strong>Bridge inspection, deflection measurement, load testing, displacement of piers and supports, structural rehabilitation and Structural Health Monitoring<\/strong>.<\/p>\n<p>You can check the <a href=\"https:\/\/guemisa.es\/en\/brand\/dimetix\/\">Dimetix range available at GUEMISA<\/a> either <a href=\"https:\/\/guemisa.es\/en\/contact-guemisa\/\">send us your application data<\/a>.<\/p>","protected":false},"featured_media":2070,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}}},"marca":[73],"industria":[106],"class_list":["post-8540","casos-de-uso","type-casos-de-uso","status-publish","has-post-thumbnail","hentry","marca-dimetix","industria-obra-civil"],"_links":{"self":[{"href":"https:\/\/guemisa.es\/en\/wp-json\/wp\/v2\/casos-de-uso\/8540","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/guemisa.es\/en\/wp-json\/wp\/v2\/casos-de-uso"}],"about":[{"href":"https:\/\/guemisa.es\/en\/wp-json\/wp\/v2\/types\/casos-de-uso"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/guemisa.es\/en\/wp-json\/wp\/v2\/media\/2070"}],"wp:attachment":[{"href":"https:\/\/guemisa.es\/en\/wp-json\/wp\/v2\/media?parent=8540"}],"wp:term":[{"taxonomy":"marca","embeddable":true,"href":"https:\/\/guemisa.es\/en\/wp-json\/wp\/v2\/marca?post=8540"},{"taxonomy":"industria","embeddable":true,"href":"https:\/\/guemisa.es\/en\/wp-json\/wp\/v2\/industria?post=8540"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}