An observation system includes an information acquiring section configured to acquire sensor information from a sensor section set in a structure and configured to detect vibration of the structure and a processing section configured to calculate information concerning a peak vibration frequency of the vibration on the basis of the sensor information and determine a surface state of the structure on the basis of the information concerning the peak vibration frequency.

A stress measurement device includes a first obtaining unit obtaining thermal data including information indicating a temperature of a measuring region, a second obtaining unit obtaining data related to stress occurring in one part of the measuring region, and a controller finding stress occurring in the measuring region from the thermal data and the data related to the stress. The controller finds, first waveform data respectively on the one part and a part other than the one part based on a change with time of the thermal data, and second waveform data based on a change with time of the data related to the stress. The controller finds, disturbance data through a deduction of the second waveform data from the first waveform data on the one part, and stress data indicating stress occurring in the part through a deduction the disturbance data from the first waveform data on the part.

A system and method for measuring dynamic properties of a structure, and for using the measured dynamic properties to assess the dynamic performance of the structure. The system and method measures dynamic properties of the structure such as frequencies of resonance, mode shapes, and non-linear damping, and uses them in an analysis of the structure to compare the dynamic response of the structure with the anticipated properties of a structure built according to applicable building code requirements. The system and method thus quantifies a risk of failure of the structure by determining a risk ratio that compares an as-is condition of the structure with an as-designed condition of the structure.

Aspects of the present disclosure describe systems, methods and structures and applications of optical fiber sensing. Of significance, systems, methods, and structures according to aspects of the present disclosure may reuse and/or retrofit/upgrade existing optical fiber cables as part of optical fiber sensing that may find important societal application including intrusion detection, road traffic monitoring and infrastructure health monitoring. Combining such optical fiber sensing with artificial intelligence (AI) further enables powerful applications at low(er) cost.

Hundreds of thousands of concrete bridges, buildings etc. and hundreds of billions of tons of concrete require characterization throughout the process from manufacture to pouring and curing and on throughout service life. The characterization may relate to initial concrete properties, projected concrete properties, framework removal, corrosion, failure etc. Accordingly, a variety of measurements such as water content, electrical resistivity, and half-cell corrosion potential for example would be beneficially implemented as easy to use field test equipment or embedded sensors allowing lifetime monitoring to be performed rather than discrete assessments when issues become evident.

The invention relates to a bridge exciter for inducing vibrations in railway or roadway bridges, which comprises a servo-hydraulic actuator connected to a wagon designed to transport the same over tracks or a road. The actuator generates a force by moving a variable-weight reaction mass guided by linear bearings. It comprises hydraulic equipment that enables direct transmission of the vibrations to the infrastructure, independent of the rolling gear of the wagon or the rubber-tired vehicle, via false wheels. The movement of the actuator piston is controlled by a computer allowing the actuator to apply general forces on a bridge or roadway that do not exceed the maximum acceptable displacement of the piston: harmonic, impulsive, and transient forces. The equipment is provided with the necessary load control elements.

A measuring system for measuring the displacement of at least one point of a bridge, wherein the bridge has a resonance frequency included in the frequency band [fl, fh] where fl<fh, the measuring system including: a geophone adapted to be applied in the at least one point of the bridge, the geophone having a resonance frequency fr greater than fh and a frequency response for f<fh substantially equal to that of a double shunt; an analogue compensation device connected in series to the geophone and having a frequency response equal to that of a double integrator in the frequency band [fl, fh]; an analogue integrator device connected in series to the analogue compensation device; and an analogue/digital converter device connected in series to the analogue integrator device, the analogue/digital converter device being adapted to convert the output signal from the analogue integrator device into a digital signal.

A stress distribution measurement method is a method of measuring stress distribution generated on a structural object including two support parts and a beam part provided between the support parts. The method includes: generating first image data by performing, through a first image capturing unit, image capturing of a moving object or an identification display object attached to the structural object from the moving object; calculating, based on the first image data, a movement duration in which the moving object moves between the support parts; generating, as second image data, thermal image data by performing image capturing of the surface of the beam part through a second image capturing unit; calculating a temperature change amount based on a second image data group corresponding to the movement duration; and calculating a stress change amount based on the temperature change amount to calculate stress distribution based on the stress change amount.

An experimental setup for three-degree-of-freedom large-amplitude free vibration in a wind tunnel test. The setup includes a rigid test model, rigid circular rods, rigid lifting arms, arc blocks with grooves, lightweight high-strength thin strings, linear tensile springs, fixed pulleys, and bearings. Large-amplitude three-degree-of-freedom free vibrations of test models can be adapted by the vertical deformation of the springs without any tilt. The possible nonlinear mechanical stiffness due to vertical spring tilt and lateral spring deflection are excluded. It is convenient to install the test model and adjust the initial angle of attack in the new experimental setup. The linear stiffness property and hence constant vibration frequency can be ensured for very large-amplitude vibrations due to the eliminations of spring deflection and tilt.

The device for measuring the structural state of a building a device for measuring the movement and/or vibration of a reference module in relation to a target in accordance with a three-axis reference system. To this end, the device for measuring includes a resilient polymer cable which conducts with variable resistivity and a vibration sensor which measures the vibrations of the building. The invention also relates to a method for monitoring at least one measurement of the structural state of a building and an installation which incorporates at least one measuring device.