Seimic performance of two rigid blocks coupled through a Maxwell visco-elastic device

Abstract

The protection against seismic hazards for rigid block-like structures, commonly modeled as rigid blocks, is often achieved by coupling such structures with external protection devices. The most commonly used protection devices include dynamic mass absorbers, oscillating masses, base isolation systems, and hysteretic mass damper inerters. Additionally, several papers have studied the dynamic and seismic response of rigid blocks connected in series, with most of them focusing on the stacked rigid block system, where the blocks are placed one on top of the other. This paper investigates the seismic behavior of a system consisting of two rigid blocks connected in series through a linear visco-elastic Maxwell device. The aim is to understand the possibility of improving the seismic response of a rocking structure (modeled by one of the two rigid blocks) by connecting it with a rocking protection device (modeled by the additional rigid block). Each rigid block can exhibit three different types of motion: full contact, rocking motion around the left base vertex, and rocking motion around the right base vertex. Consequently, during the motion of the coupled system, nine different combinations can occur, each of which is described through a specific set of equations of motion. A parametric analysis is performed with the aim of investigating how the characteristics of the additional rigid block and connection device affect the seismic behavior of the main rigid block (the one modeling the rocking structure). The assessment is carried out through a comparison between the displacements of the coupled system and those of the stand-alone blocks. The results, organized in gain maps, show that there are several combinations of the characteristics of the additional rigid block and connection device that lead to an improvement in the seismic behavior of the main rigid block.