Situation
A large building of 5 two-storey Units, and 5 garages (walls reinforced concrete tilt panels, floors reinforced concrete). During re-levelling, the weight of the building when floating on the Hydraulic Jacks, was approximately 618 tonne.
The front 4 Units and west wall of the 5th Unit were re-levelled using Jack and Pack for the perimeter Foundations and walls. The reinforced concrete ground floor slabs were re-levelled using steel trusses, and threaded steel rods temporarily set into the floors.
Prior to re-levelling, the Geotechnical Report showed the floors had a Level difference of over 100mm, and Grades in excess of 1.6%.
The floors were re-levelled to within 7mm within the Units (±10mm within the Garages). Evidence before re-levelling showed the floor levels varied considerably prior to the Earthquakes, so the ground floor after re-levelling was considered to be more level than it ever was.
After the floors were re-levelled, Grout was pumped through holes in the floors to fill cavities below, and the filling checked by ground-penetrating radar to ensure there were no cavities left unfilled below.