Use of Sloped Bases for the Seismic Protection of Non-Symmetrical Rocking Objects

This paper uses analytical, numerical and experimental approaches to investigate the seismic protection of freestanding non-symmetrical objects through a simple, although efficient method of locating them on sloped bases. A novel model is proposed for a non-symmetrical block with a flat bottom rocking on a compliant sloped base. Pseudo-static analytical results based on this model are used to predict the optimum base slope for improving the rocking behavior and show that the proposed method will be more effective for blocks that are smaller, stockier and more non-symmetrical. Numerical and experimental results are then used to demonstrate the efficacy of the proposed method and show that the trends identified with the pseudo-static analytical results are also applicable when the dynamic behavior of the block is taken into account. From the results in this paper, the use of sloped bases could be a viable method for the seismic protection of freestanding non-symmetrical objects. The advantages of the sloped base method are that it is financially cheap, it does not require any space around the object, and it does not require moving parts or intrusive mechanical connections. The main application of the sloped base method considered in this paper is the seismic protection of freestanding historical artifacts in museums, but it could also be used for other types of freestanding objects with suitable geometry.