Bridge & large structure monitoring

See how load moves through the whole structure.

A bridge is a connected load path. Distributed fiber sensing follows strain, temperature, deformation and vibration across that path instead of reducing the structure to a few isolated points.

Explore the monitoring approach View field cases

The useful measurement is not one strain value—it is how the response changes across the span.

The monitoring question

Where does the structure change—and is that change expected?

Traffic, wind and temperature do not act at one point. Their effects travel through decks, girders, bearings, cables and connections. Sparse sensors can verify selected locations, but they can miss the transition between them.

The system therefore begins by defining the load path, the required spatial coverage and the time scale of the behavior before selecting the sensor cable or interrogator.

Monitoring plan

Match each structural question to the right measurement.

Global load response

Distributed strain profiles along girders and decks show how load is transferred across the span.

Strain distribution

Thermal movement

Spatial temperature data separates thermal expansion from load-induced strain and supports compensation.

Temperature field

Local critical zones

Denser arrays or point FBG sensors focus on bearings, joints, cable anchorages and known stress concentrations.

Local strain / displacement

Dynamic behavior

Dynamic strain or acoustic sensing captures vibration as vehicles, wind and transient events excite the structure.

Vibration response

Sensor placement follows the structural load path and the areas where change must be resolved.

The sensing chain

Field data depends on more than the grating.

The array, cable structure, bonding method, interrogator and interpretation model must transfer the same physical event without losing its spatial meaning.

01Define coverage and spacing
02Transfer structural strain into the fiber
03Locate and demodulate each response
04Compare the measured profile with the structural model

Field reference

Jinhai Bridge: monitoring the box girder as a spatial system.

UW-FBG arrays were arranged along the bottom plate and webs of the 340 m main-span box girder. The layout was used to recover strain and deformation under static and dynamic loading rather than relying on a single instrumented section.

Asset: Cable-stayed bridge box girder
Coverage: Bottom plate and left/right webs
Measured behavior: Strain and deformation response

Read the field case

Jinhai Bridge, Zhuhai.

Related field evidence