Behaviour of self-centring shear walls——A state of the art review

The application of unbonded post-tensioning (PT) in structural walls has led to the development of advanced self-centring (rocking) shear wall systems that has significant advantages, including accelerated construction due to the incorporation of prefabricated elements and segmental construction for different materials (e.g., concrete, masonry, and timber), reduced residual drifts, and little damage upon extreme seismic and wind loads. Concrete, masonry, and timber are often used for the construction of unbonded PT structural wall systems. Despite extensive research since the 1980s, there are no well-established design guidelines available on the shear wall configuration with the required energy dissipation system, joint’s locations and acceptance criteria for shear sliding, confinement, seismic performance factors, PT loss, PT force range and residual drifts of shear walls subjected to lateral loads. In this research a comprehensive state-of-the-art literature review was performed on self-centring shear wall system. An extensive study was carried out to collect a database of 100 concrete, masonry, and self-centring shear wall tests from the literature. The established database was then used to review shear walls’ configurations, material, and components to benchmark requirements applicable for design purposes. The behaviour of concrete, masonry and timber shear walls were compared and critically analysed. The general behaviour, force-displacement performance of the walls, ductility, and seismic response factors, were critically reviewed and analysed for different self-centring wall systems to understand the effect of different parameters including configurations of the walls, material used for construction of the wall (concrete, masonry, timber) and axial stress ratio. The outcome of this research can be used to better understand the behaviour of self-centring wall system in order to develop design guidelines for such walls.

Self-centring segmental retaining walls—A new construction system for retaining walls

This paper reports on an experimental study on a new self-centring retaining wall system.Four post-tensioned segmental retaining walls(PSRWs)were experimentally tested.Each of the walls was constructed using seven T-shaped concrete segments with a dry stack.The walls were tested under incrementally increasing cyclic lateral load.The effect of the wall height,levels of post-tensioning(PT)force,and bonded versus unbonded condition of PT reinforcement on the structural behavior of the PSRWs was investigated.The results showed that such PSRWs are structurally adequate for water retaining structures.According to the results,increasing the wall height decreases initial strength but increases the deformation capacity of the wall.The larger deformation capacity and ductility of PSRW make it a suitable structural system for fluctuating loads or deformation,e.g.,seawall.It was also found that increasing the PT force increases the wall’s stiffness;however,reduces its ductility.The residual drift and the extent of damage of the unbonded PSRWs were significantly smaller than those of the bonded ones.Results suggest that this newly developed self-centring retaining wall can be a suitable structural system to retain lateral loads.Due to its unique deformation capacity and self-centring behavior,it can potentially be used for seawall application.