Lifting a 150 tonne building at the Wingham Brush Public School…
The stairwell had been added some 20 years later to the school building. It was not on satisfactory footings and began to settle and tilt. I evacuated this area of the school until the work was done. Earlier attempts at rectification had been tried, but the material injected under the building simply filled the adjacent downpipes and cracks etc. It also lost support letting the stairwell continue to subside.
In the picture, the left hand pile is a compression pile. It has a red 20 tonne hydraulic jack sitting on it. The jacks were removed before backfill.
The right hand pile is a tension pile. Note the channel beams are bolted to the pile so the pile can hold the beams down.
The stairwell weighed some 150 tonne and we lifted it back to about 40% of its original position. We couldn’t go any further as we would have damaged the connection between the stair and the classroom building.
All the steel was encased in concrete to add to its life. Thicker steel wall sections were selected to increase the life to 100 years minimum.