A coordinative scaled model design method with attached plates for underwater shaking table tests

Abstract

Structures located in the water environment undergo additional hydrodynamic forces induced by fluid–structure interaction under earthquakes, which could increase the dynamic responses and affect the seismic performance of underwater structures. Underwater shaking table tests are generally used to verify the seismic performance of structures by using scaled models. Unlike the traditional shaking table without water, it is difficult to design the scaled model as the traditional similitude law requires the designer to change the mass density of water, which is impossible in reality. As a result, the mass density similitude ratio of water mismatches with that of the specimen, which leads to an inconsistent scale of the hydrodynamic forces and the inertia forces of the specimens. A new scaled model design method based on the coordinative similitude law is proposed. This increases the hydrodynamic forces of the model using attached plates to ensure the consistency of the similitude ratio of hydrodynamic forces and inertia forces. A series of numerical simulations are conducted in ADINA (finite element software) to validate the proposed coordinative scaled model design method with attached plates by comparing with the conventional scaled model (CSM) designed based on the artificial mass modeling method and the prototype under unidirectional and bidirectional earthquakes coupled with hydrodynamic forces. The results show that the maximum relative error of dynamic responses could reach 82.80% between the CSM and the prototype; while it is 25% between the coordinative scaled model with attached plates and the prototype. The coordinative scaled model with attached plates can reproduce the responses of the prototype with high accuracy, and thus it is recommended to be used in the underwater shaking table tests.