Bridge Deflection Calculating Using Accelerometers
Overview
This page introduces case studies and software for measuring displacement of railway and road bridges using Epson's quartz-based accelerometers.
In bridge maintenance, displacement is a critical indicator. It is used for serviceability evaluation defined in the Specifications for Highway Bridges by Japan's Ministry of Land, Infrastructure, Transport and Tourism.
Traditionally, displacement measurements rely on contact-type displacement gauges or laser displacement sensors. They require fixed reference points and are susceptible to weather conditions. These limitations have restricted widespread adoption.
To address these challenges, a method has been developed and put into practical use that estimates displacement from acceleration data measured by accelerometers installed on bridge components. This approach eliminates the need for reference points and is unaffected by environmental or weather conditions.
Road Bridge
Displacement Estimation Software: Epson Bridge Deflection Calculator
We provide the Epson Bridge Deflection Calculator, a software tool that calculates bridge displacement by integrating acceleration responses during vehicle passage. The software processes acceleration data measured by Epson accelerometers ( M-A352/M-A552/M-A370 ) and outputs estimated displacement results. It also allows comparison with reference displacement data obtained from contact-type gauges.
Application Example
An accelerometer ( M-A552 ) was installed on a mock bridge, and displacement was estimated using the Epson Bridge Deflection Calculator. The figure below shows time-series data of estimated displacement (blue line) versus reference data from a contact-type gauge (orange line). The results demonstrate excellent agreement between the two measurements.
Download Package
You can use the displacement estimation software on your PC.
| File | Description |
|---|---|
| Epson Bridge Deflection Calculator Package (ZIP, 50MB) | Includes the following files:
See individual sections below for details. |
Documentation
| Document | Description |
|---|---|
| Epson Bridge Deflection Calculator User Guide (PDF, 637KB) | Manual for using the displacement estimation software. |
Software
We provide both executable files and Python source code.
| Program | Description |
|---|---|
| Executable File (ZIP, 49MB) | Epson Bridge Deflection Calculator software. Refer to the user guide for instructions. (Includes EXE file only; Python source code not included.) |
| Source Code (Python) (ZIP, 1.9MB) | Python source code for Epson Bridge Deflection Calculator. (Includes Python code only; EXE file not included.) |
Sample Data
| Sample Data | Description |
|---|---|
| Mock Bridge Data (CSV, 72KB) | Contains accelerometer output (Column B) and reference displacement gauge data (Column C) used in the application example. Compatible with Epson Bridge Deflection Calculator. |
Railway Bridge
We also introduce a case study of displacement estimation for railway bridges using accelerometers.
Example: Measuring Displacement During Train Passage
An Epson quartz accelerometer (M-A352AD10) was installed on a two-cell box girder railway bridge to measure displacement during train passage. Displacement calculated by double integration of acceleration data closely matched results from a contact-type displacement gauge. For details, see the case files below.
| Case Files | Description |
|---|---|
| We tried Measuring a Bridge with an Accelerometer! (Measurement data csv file included) | Explains measurement methods and provides data from railway bridge tests. |
| We tried Analyzing a Bridge with an Accelerometer! | Introduces analysis of the measured data. |
Practical Example: Remote Monitoring Device
Epson, in collaboration with East Japan Railway Company and Nagano Keiki Co., Ltd., successfully developed and commercialized a remote monitoring device for steel bridge bearings. This device uses Epson's M-A352 accelerometer to automatically measure the magnitude of the vertical movements, or deflections, of girders during train passage and sends data via email, automating a task previously performed manually.
For details, please refer to our news release.
Technical Papers
Our technical papers section features numerous studies on displacement estimation using Epson accelerometers.
