The Dorset Street Flats have been badly damaged in the earthquakes that have struck Christchurch in the years following and including the initial 04 September 2010 earthquake.
We've been commissioned by the majority insurer (Southern Response) and approved by the other insurers involved (IAG, Medical Assurance, and Tower Insurance) to work with their project managers Arrow International, and complete the documentation for the repair of the Dorset Street Flats.
This is a huge honour, as these buildings are among the most important in New Zealand's architectural history.
Greg Young, the managing director of Young Architects, is probably the most qualified person in New Zealand to be undertaking the lead of this repair, after working for both the original structural engineers (Holmes Consulting Group) and architects (Warren and Mahoney Architects). Greg has met with Heritage NZ, Christchurch City Council heritage, and also Sir Miles Warren, to discuss how the repair is approached.
These buildings were recently featured on TVNZ's The New Zealand Home (https://www.tvnz.co.nz/ondemand/the-new-zealand-home).
We're currently working through the construction detailing with the engineers and contractors, and will then be updating this regularly as we progress on site.
We were commissioned to produce the repair documentation for The Dorset Street Flats in 2015. We produced the building consent documentation for the insurance based repairs in mid 2017, and finally in July 2019 satisfactory settlements have been reached by the owners with their respective insurance companies ... FINALLY ...
We're currently tidying up the documentation for the actual repairs (rather than the theoretical repairs to meet insurance policy requirements), and will soon be ready to start work on site.
All ducks are in a line, ready for a start.
Resource consent approved.
Building consent approved.
Construction contract signed with SummitBuild.
Mainmark about to commence releveling the foundations.
Mainmarks equipment is delayed in customs with border security tightening up around the world ... we'll be starting the re-leveling "soon"...
The re-leveling is underway. Mainmark are using the same technology that was used to relevel the Christchurch Art Gallery, and heritage projects in New Zealand and around the world.
Not a lot to comment on as of yet, apart from the confidence I feel with the international experts on site.
The re-leveling is complete.
This was a complicated assessment to make. One of the most important ways the construction detail was originally articulated, was in how different elements of the building aligned with each other - the joinery was aligned with blockwork grout lines for example.
During the releveling process we assessed the alignment of the blockwork between the two buildings, the horizontality of the coursing, how level the first floor slab was (the ground floors are too broken to use accurately), how parallel the seismic joint was between the buildings ... as well as how the ground was performing, whether cracking in the cladding opened/closed, whether the cladding was being displaced out of plane ...
On Monday the building started giving some resistance to the releveling process. We've brought the buildings up approximately 50mm, aligning the coursing between the two buildings, and re-establishing the seimic gap to being parallel ... and there the buildings wanted to stop. The resins used in the process started to be refused, and blockwork started to be displaced. If we continued to bring the floors to be more level, then the blaockwork would move out of alignment, and the seismic gap would be out of parallel.
This is where we think the building was originally positioned. To double check, we've checked how level the sliding doors are, and they're now where we want them to be for the doors to be able to be used easily.
We're now moving forward into the repair of the buildings themselves, comforable with the repairs to the ground and existing foundations.
After digging out within the walls to a depth that Willy Marshall at Engeo was comfortable with (by hand with shovels and wheelbarrows), we've now set up with a layer of gravel and crusher dust to the level required for the DPM / insulation / structural slab.
There was some momentary acceleration of pulse with some crockery and bones being found during the excavation, but after Heritage NZ were consulted, we were given permission to continue (our joke about KFC fell on deaf ears) - this was determined to be 1930's / 1940's so of no interest in an archaeological sense, but the artifacts have been kept for the owners own interests.
So far we have Flats 14 & 16 with new floor slabs. These floors are a completely different approach to the originals. The original concrete slabs were 4" (100mm) thick, unreinforced, poured directly onto dirt, floating between the walls.
The new slabs are 300mm thick, heavily reinforced with two layers of ductile steel bars, insulated underneath and around the perimeter, and tied into the foundations. There is so much steel in the new floors that we've had difficulty getting plumbing set up.
The existing copper plumbing has recently been stolen by some low life pond scum. The Police are investigating nearby security cameras, and we're setting up some security cameras and flood lights on site. Broken bottles and razer wire has been discussed, but decided against due to not being a politically correct approach.
The new floor slabs also heated with water pipes - no more woolly jumpers required!
After a marathon effort, the walls are reinforced, and structural steelwork installed internally. There is A LOT of structure in The Flats now - much more so than we normally see in residential construction - ready to face the next sixty years from a significantly stronger position.
We're now working through external joinery installation. The biggest challenge is that nothing is prefectly straight or consistent. Joinery is needing to be built out of square to get the critical alignments correct. It would seem that was the same approach as the original construction, which is giving the carpenters a headache - they don't like being told to build something crooked so that it looks right ...