Three-Point Bending Test of Concrete Beam

Three-point bending testing is a common method for evaluating the flexural strength and crack propagation behavior of concrete beams. In this test, the concrete beam is subjected to a concentrated load on supports, causing bending deformation at midspan. Conventional strain measurement methods usually rely on contact sensors such as strain gauges and cannot fully capture the full-field strain distribution of the beam, especially during crack formation and propagation.

The Haytham monocular 3D visual strain gauge adopts monocular 3D digital image correlation (DIC) technology to perform real-time, non-contact full-field measurement of the surface strain of concrete beams in three-point bending tests. The device captures images of the beam surface with a high-resolution camera and computes the strain distribution during loading using image processing technology. Compared with conventional point measurement methods, it provides strain distribution maps of the entire beam surface, delivering critical stress and strain information especially in crack formation regions.

In the three-point bending test, the concrete beam is placed on two supports while the loading device applies a gradually increasing load at midspan. The Haytham monocular 3D visual strain gauge monitors the deformation of the beam surface in real time through a high-speed camera. As the load increases, the device captures the strain distribution in different regions of the beam under load, particularly the changes in the maximum strain region at midspan and in the crack propagation region.

By analyzing the full-field strain data, engineers can gain a detailed understanding of the stress concentration and crack propagation behavior of the concrete beam under three-point bending loads. These data are essential for evaluating the flexural performance of the beam, identifying potential structural weaknesses, and predicting its service life. In addition, the strain data can be used to validate finite element analysis models and optimize the design of concrete beams to improve structural safety and durability.