Numerical Investigation of River Ice-Bridge Pier Interaction

Rivers freeze in most North America areas in winter season. The thick ice sheets formed around bridge piers will not only change the constraint or boundary conditions of bridge structures, but also generate great forces on bridge piers under earthquake loading. The ice-pier interaction was deemed as the main reason that caused failure of bridges in South-central Alaska during the 1964 Great Alaska Earthquake. Figure 1 shows two examples of the damages occurred to the highway bridge piers. River ice increases the lateral constraint stiffness to bridge piers, hence reduces its free length and causes the formation of short piers. Short piers are notoriously known for their much weaker resistance to shear force than long piers. The interaction mechanism between ice sheet and bridge pier has to be understood in order to investigate its impact on the seismic performance of highway bridges in cold regions. This paper presents the interim results from the analysis of river ice-bridge pier interaction process.