Shake table testing and finite element modeling of a modular bridge-like model with controlled rocking piers

This study presents the results of triaxial shake table testing and three-dimensional (3D) finite element (FE) modeling of a modular bridge-like specimen. The specimen comprised four prefabricated reinforced concrete (RC) cylindrical columns capped with a slab. The structural connections were non-monolithic, allowing controlled relative motion of the members (rocking and sliding). The columns were connected to the slab with stiff tendons that provided positive post-uplift stiffness. The specimen was subjected to 184 triaxial shake table tests. Subsequently, a detailed 3D FE model of the specimen was developed and validated statistically. The objectives of the study were to: (i) investigate the triaxial shake table response of a modular bridge with positive post-uplift stiffness, (ii) develop an FE model of the proposed system, and (iii) investigate the influence of geometrical imperfections on rocking structures. After 184 shake table tests, the specimen showed zero damage, moderate displacements and tendon forces (TFs), low slab torsion, and zero residual displacements. The proposed FE model accurately captured the statistics of the experimental response. Results showed that negative stiffness systems are sensitive to geometrical imperfections, whereas positive stiffness systems are not.