ANGEL GARDENS, MANCHESTER, UK

CCL designed a combination of post-tensioned (PT) and traditional reinforced concrete solutions for this landmark luxury development in Manchester.

Slabs from level 1 upwards were installed as PT concrete but level 8 and above required an understanding of deflection implications and the need to position the PT tendons to manage these effectively. In collaboration with the project’s engineers, CCL used the PT slab design to manage the deflections and avoid the need for a concrete corbel within the slab footprint.

The PT slab design also had to consider positioning of the PT tendons and anchors to avoid any buildability challenges for other construction elements. Consequently, tendon and anchor locations were designed around the requirements of the cladding design and balcony fixings.

CCL designed and installed 63 slabs in total across the tower and four smaller blocks and was also involved in other elements of the concrete design strategy including the beams supporting both the cantilevered section and the atrium bridges.

Both RC and PT options were considered for the beams, taking into account soil pipe and stub stack penetrations that the architect had designed in to conceal drainage services. These penetrations were fixed within the design layout, so there was little flexibility for positioning of PT tendons. Close-centred cladding connections on the beam ends presented further challenges for PT in the beams. Despite the increased beam width and level of steel reinforcement required, CCL advised an RC design strategy for the concrete beams and was able to leverage maximum benefits in terms of buildability and project management.