Development of a direct force-measuring technique for breakwater models in flume tests

Assessment of the forces acting on breakwaters in flume tests, including horizontal forces and overturning moments, has traditionally relied on indirect methods, such as integrating pressure distributions over the surfaces of the breakwater models. While applicable for relatively regular structures like caissons, seawalls or box-type floating breakwaters, these methods are less applicable or accurate if the breakwater has a complex shape. This paper presents the development, calibration and validation of a direct force-measuring device for wave flume tests. The device is designed to accommodate replaceable breakwater models and to measure resultant forces through reactions transferred to a base structure without intruding into the flow field. Its performance is first examined under controlled periodic loading and then evaluated in regular-wave tests using an impermeable vertical wall, with comparisons against pressure integration and the Goda (1974) formulation. The results show good repeatability and consistency with existing mainstream methods.