Unbonded post-tensioned shear walls of calcium silicate element masonry

CASIEL masonry consists of prefabricated calcium silicate elements (CASIELs) that are bonded by thin-layer mortar. In Northwest Europe, CASIEL masonry is popular for application in shear walls in low- to medium-rise buildings. Theoretically, the horizontal load capacity of such shear walls can be increased by a prestressing technique called unbonded post-tensioning (UPT). The research described in this dissertation was aimed at collecting experimental evidence for the mechanical behaviour of UPT CASIEL masonry shear walls and at developing mechanical models and design rules for such shear walls. The investigation was confined to UPT by means of high-strength steel tendons, monotonic horizontal loading and two types of CASIELs with a high compressive strength. The following aspects of UPT CASIEL masonry shear walls are considered in this dissertation:- Prestress loss due to creep and shrinkage of high-strength CASIEL masonry;- Mechanical behaviour of UPT CASIEL masonry shear walls acting as a cantilever, with particular attention to activation of the UPT tendons due to uplift of the wall;- Redistribution of horizontal load among shear walls in a building upon cracking. Based on the results of these investigations, recommendations are made for design rules and construction guidelines of UPT CASIEL masonry shear walls, followed by general conclusions and recommendations for further research.