The investigation of post-construction intervention techniques on a double-skin concrete blockwork wall

Abstract

The main focus of this experimental analysis was to investigate if remedial wall ties can be utilised as post-construction intervention techniques within double-skin hollow concrete blockwork. In this research, studies were carried out and results were compared to other researcher’s analyses. The local construction society predominantly uses hollow concrete blockwork as the parent material for building. As materials for the investigation, hollow concrete blocks and mortar were used. In this analysis, four test walls were conducted, two of which were applied with steel Dryfix ties, with the other two being applied with rolled GeoSteel ties. The mortar utilised within the wall specimens was an M4 mortar mix. The main testing procedure involved the application of horizontal loading at mid -height with the use of a testing rig. Recorded results of the Dryfix walls registered primarily horizontal cracking bending failures and one of the walls showed bed-joint shear failures above the loading beam. On the other hand, the rolled GeoSteel tie wall specimens showed a high bending capacity as one of the wall specimens registered a bending failure whilst the other recorded a sliding shear failure within the bed joint. Results also showed that all four walls reached a relatively high horizontal applied load. From the results, the Dryfix and the rolled GeoSteel tied walls registered different scenarios regarding technical data. The Dryfix walls recorded low horizontal displacements while the rolled GeoSteel walls barely had any deflection at mid-height. Also, in the walls, the loaded leaf registered a slightly higher deflection than the tied leaf, which showed that the load transfer was occurring. This meant that the remedial wall ties tested were considered a success for retrofitting double -skin hollow concrete block wall structures.