Three-Point Bending DIC Test of Transverse Wet Joint

Wet joints are key connection nodes in concrete box girder bridges, where precast girder segments are typically joined into an integral structure with cast-in-place concrete; their stability directly affects the load-bearing capacity and safety of the bridge. However, wet joint technology in current bridge construction still faces many challenges, including issues such as structural form and filler quality. These factors play an important role in improving the ultimate load-bearing capacity of the structure and are of practical significance for advancing the technological development of prefabricated bridges.

Model diagram

In this test, the Yantan transverse wet joint was selected as the object for three-point bending testing. During the test, speckle points were applied on the girder surface and stepwise loading was performed to simulate the displacement, deformation, and crack resistance of the girder under load. The test sampling frequency was 0.2 Hz, with a loading increment of 5 KN per step and a maximum load of 40 KN.

Using the Haytham binocular 3D visual strain gauge to perform multi-point displacement measurement of the specimen in three directions (X, Y, Z), outputting the displacement-time curves shown in the figure.

Z and Y displacement results under stepwise loading

Meanwhile, the strain contour maps of the measurement area and the multi-point strain curves were analyzed to comprehensively evaluate the strain distribution and load-bearing performance of the joint. In the subsequent flaw detection process, the Haytham binocular 3D visual strain gauge was easy to install and remove, greatly improving testing efficiency.

Strain results under stepwise loading

Compared with traditional sensor arrangements, Haytham binocular 3D visual strain gaugeoffers the following advantages:

1. 3D full-field displacement and strain measurement, with velocity and acceleration calculation functions;

2. Ability to track motion trajectories and analyze crack propagation paths;

3. Flexible adjustment of measuring range and standoff distance, supporting wide-range testing up to 10 m;

4. Modular design, allowing convenient replacement of cameras and lenses to meet different testing needs.

Haytham's DIC technology not only delivers accurate and reliable test results but also simplifies the operating procedure, providing an innovative solution for structural health monitoring of bridges.