Monotonic and cyclic load behaviour of helical pile connectors in the vertical direction

Abstract

The helical pile is a foundation system that is used to support new residential and commercial buildings and to stabilize repairs of existing structures. It represents an attractive option to upgrade the seismic resistance of foundations. This necessitates a good understanding of the seismic performance of the specialized connectors linking the pile shaft to the concrete foundation. An experimental program is initiated at The University of Western Ontario to investigate the seismic performance of these connectors, to develop models that can be used in finite element analysis to describe their behaviour, and to propose modifications to enhance their seismic performance, if necessary. In this program, eight specimens were tested to assess the behaviour of two types of these connectors under different loading modes. It was concluded that connectors with an uplift bracket are required for seismic applications to control uplift displacement due to rocking of the foundation.Key words: helical pile, connector, experimental, model, monotonic load, cyclic load, foundation, stiffness, strength.