Rocking Isolated Frame Structures: Margins of Safety against Toppling Collapse and Simplified Design Approach

摘要: Abstract This paper aims to explore the limitations associated with design of “rocking - isolated” frame structures. According this emerging seismic concept, instead over-designing isolated footings a (as entrenched in current capacity–design principles), latter are under-designed intention limit loads transmitted superstructure. An idealized 2-storey is utilized as an illustrative example, investigate key factors affecting foundation design. Nonlinear FE analysis employed study performance rocking-isolated frame. After investigating margins safety against toppling collapse, simplified procedure developed estimate minimum acceptable footing width B min , without recourse sophisticated (and time consuming) numerical analyses. It shown that adequate collapse may be achieved, if displacement capacity δ topl (i.e. maximum horizontal does not provoke toppling) sufficiently larger than demand dem . With respect use appropriate “equivalent” rigid-body suggested, and yield conservative The estimated on basis spectrum, peak spectral SD max proposed measure validity such approximation investigated for rigid-block rigid-base utilizing rigorous analytical solutions from bibliography; structure nonlinear soil, by conducting comprehensive dynamic history In all cases examined, approach reasonably estimates.