Abstract

Starting with Housner (1963), many researchers have suggested that rocking systems with gapping under the base have an inherent re-centering mechanism that helps them remain stable during dynamic loading. But, the profession seems resistant to routine use of rocking foundations for buildings and bridges for a variety of reasons:

1) unreasonable fear of tip-over instability

2) uncertainty about the magnitude of settlement associated with rocking

3) natural uncertainty of soil conditions

4) lack of understanding of the benefits of re-centering

5) dissemination/demonstration to practising engineers

6) lack of accepted/approved design procedures

This lecture reviews nearly a decade of research work to address these issues. The work included centrifuge modelling of dynamically loaded individual foundations and soil-footing-column-structure systems. Numerical simulations include different methods of modelling the gapping, sliding and yielding at the footing-soil interface and have included large deformation effects to show that rocking footing systems have superior stability compared to hinging column systems. Recent work has included significant interaction between practising and academic and geotechnical and structural engineers to address items (5) and (6). The talk concludes with reflections on how academic engineers can more effectively influence practice.