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House & Housing Projects

Disraeli Court, Hereford


Disraeli  Court in Hereford, a sheltered housing development owned by Herefordshire  Housing Ltd, was suffering from subsidence problems so severe that the facility  had to be closed and the residents moved out. Several repair schemes were  investigated and rejected and even demolition and rebuilding was being  considered until structural repair specialist, Helifix Ltd, proposed a  cost-effective scheme that would restore structural integrity and also be  covered by a 10 year warranty.

Disraeli  Court comprises a communal building of 30 flats plus two self-contained annexe  bungalows, all constructed with vibro pile foundations on a land fill site.  Investigations showed that the foundations had started to fail as organic fill  within the ground had decayed, causing the buildings to subside and generating  widespread external and internal cracking, distortion of openings and  settlement of the floor slabs. By 2008 the damage was so great that it was no  longer suitable for residential purposes.

With  the approval of project managers and engineers, G Fulford & Co, the  Helifix repair scheme proposed a combination of foundation stabilisation and  super-structure masonry repairs, undertaken by their Approved Installer working  to main contractor, E G Carter & Co. Foundations beneath all external and  internal load bearing walls were stabilised by installing 417 Helifix micro  piles, between 3m and 7m in length, at approximately 2.5m centres. To minimise disruption  to the internal floor slab, external walls were supported by piles installed on  the outer face fitted with foundation support brackets jacked up beneath the  existing footings. The internal walls were supported either by foundation support  brackets or new reinforced concrete needle beams cast onto the pile head,  spanning beneath the walls to provide support.

Access  to internal load-bearing walls was severely restricted but the portability of  the Helifix micro pile system made it ideal as the pile sections and hand-held hydraulic  drive head could be easily manoeuvred through doorways. No large equipment is  required and excavations are minimal. The correlation between pile driving  torque and pile bearing capacity makes the Helifix micro pile system a very  accurate means of structural support. This was important as ground conditions  across the site varied considerably, so the ability to accurately assess the  bearing capacity of each pile, as it is installed, avoided the potential risk of  installing into unsuitable material.

To  reinforce and secure the superstructure and spread the loads between the micro  piles, masonry beams were created from the existing brickwork by bonding pairs  of stainless steel HeliBars into the mortar beds. Further single HeliBars were  used to undertake extensive crack stitching on both the internal and external  walls, with well over 6,000m being installed in total.

The  cost-effective Helifix repair scheme, with 10 year warranty, fully secured  Disraeli Court, avoiding demolition and enabling refurbishment of the lift and  fixtures and fittings prior to redecoration and the reoccupation of this  sheltered housing facility by elderly residents.