engleski

Numerical and experimental investigation of collapse modes in stacked structures

Structures that consist of multiple rigid blocks stacked one on top of another, such as historical monuments, dry-stone walls and domes, Advanced Gas-cooled Reactor blocks in nuclear-power plants, or masonry components upon bond failure, respond to dynamic excitation in sense that cannot be explained by standard eigen-analysis. During earthquakes such structures undergo complex dynamic response with multiple contact discontinuities - a combination of rocking, sliding and jumping - which can result in structural failure. Given sufficient friction at all the contacts, the dynamic response of a multi-block stack to a ground excitation mainly consists of pure rocking with negligible sliding and jumping. In this work, the highlight is put onto the excitation conditions that cause specific collapse modes of two- and three-block stacks: partial collapse (only one or several top bodies overturn) or total collapse (the whole stack overturns). The excitation conditions that cause different failure modes are investigated numerically and experimentally on a novel set of experiments. The experimental programme is conducted using a biaxial shaking platform and a system of high-speed cameras for contactless optical measurement. Rocking-stability graphs for multi-block stacks subject to simple ground excitation are obtained and proposed as benchmark cases for validation of complex numerical platforms widely used to simulate multibody dynamics in practice.

rocking ; stacked structures ; dual-block stack

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