Reinforcement

Novel Reinforcement systems

The department has been involved in developing and testing prototype reinforcement systems. The Wireball system developed by Bjorn Svedberg has been the main focus of this work. This system replaces or supplements traditional bar reinforcement with interlocking reinforcement spheres. This system confines the concrete efficiently and this enables the concrete to develop greater compressive stresses. This reinforcement technique is suited to column reinforcement and testing has shown that it improves the performance of columns subjected to seismic loading.

GRP Bars

The structural and creep performance of concrete reinforced using glass reinforced plastic bars has been investigated to assess its suitability for use in a marine environment.

Fibre reinforcement

The department has done extensive work on different fibre reinforcing systems including both steel and synthetic fibres. The research on the alignment of steel fibres within a concrete slab is quite novel. When fibres are mixed randomly within concrete only a small fraction of the fibres will be aligned usefully. However, if the position and alignment of the fibres is controlled then maximum benefit can be gained. Work is ongoing on the active alignment of steel fibres using magnetic fields. The results to date are very promising. One interesting use of the fibres has been to apply an electric current through the fibre-saturated layer: this results in an elevated internal temperature which accelerates drying of the slab.

Wireballs

Wireballs are open sphere’s of wire, spun in three orthogonal directions. With rings added, they form a unique type of reinforcement for concrete in which the confinement of concrete contained within the sphere is enhanced. The performance of concrete construction details for seismic loading have been tested by carrying out full scale structural testing using Wireballs within the conventional reinforcement. These tests involved cyclically loading test pieces at high strain. This research has been undertaken with Prof. Brian Broderick as the principal investigator.

Project coordinator: Associate Prof. Roger P. West