CALCULATIONS OF MULTIPLE POUNDING FORCES BETWEEN GIRDER AND PIER OF BRIDGES UNDER VERTICAL EARTHQUAKES

Using the artificial earthquake ground motion in the form of a sinusoidal excitation, the theoretical solution of multiple elastic poundings between girder and pier of a single-pier and two-span bridge model under vertical earthquakes is derived from the expansion of transient wave functions in a series of eigenfunctions. The calculation method of multiple pounding forces is presented based on the transient internal force of the contact surface of the combined impact body. The numerical results show that the presented method can simulate reasonably the multiple-pounding phenomenon between girder and pier under vertical earthquakes. The multiple pounding force responses can be calculated in high precise. The propagations of earthquake wave and the pounding-induced transient waves throughout girder and pier can be depicted. The sub-pounding process can be observed from the numerical simulations as well.