Tricky lifts at the Cathedral
Work got back under way at our Christ Church Cathedral Reinstatement project when we reached Alert Level 3 with a couple of tricky crane lifts.
These lifts had been planned in the weeks leading up to the lockdown, and are a key part of the approach being taken to reduce worker exposure time next to the earthquake damaged building.
The first involved lifting a 14 metre long, 8 tonne concrete capping beam onto the top of an existing wall line, while threading it beneath two diagonal props that are securing an adjacent wall. This lift took 3 cranes, a propping tower, 13 lifting eyes and 5 rigging changes during the lift to move it under the props and land it in its final position. The beam had been pre-cast on the ground in a safe zone on the site, avoiding the need for workers to be forming, propping, pouring and then stripping this beam beside a part of the building that is not yet stabilised, spanning over a large window opening that had already been deconstructed.
The second involved a single 250 tonne crane lifting a 12 x 11 metre L-shaped foundation cage weighing 12 tonnes into place. This was lifted from where it had been tied in a safe area of the site to its final position next to a very damaged part of the building. To get there, it needed to travel over the site fence, tram lines and street, requiring road closures, de-powering of the tram lines, and night works. The foundation cage was prepared with all its components in place, including all reinforcing, a steel beam holding all cast-in hold down bolts together in their correct positions, speedform, reo chairs, and even lifting eyes for when the temporary foundation needs to be removed in the future.
Both lifts went off without a hitch, just as planned. A big thank you to all involved in getting this work re-scheduled and completed so soon after we made it back to level 3.
