Viking, the houses were apparantly designed and built in accordance with NZS 3604 or earlier code requirements so I guess they would contain whatever steel mesh or reinforcing was required at the time.
Another quote " Concrete slabs and pile foundations were observed to perform very differently on liquefied sites. This was clearly illustrated at an Avondale residence consisting of an older (1950"s) house, partly built on concrete pile foundations and newer (1997) extensions built on a concrete slab. The older part of the house on piles remained relatively plumb compared to the newer part. The large settlements of the slab foundations caused extensive structural damage at the interface between the old and the new structure. Similar observations were made on sites where a garage or carport on a concrete slab was connected to a house on pile foundations, giving differential movement between the two foundation types resulting in damage to the wall and roof structure of the building. In general, for areas where there has been soil liquefaction, pile foundations performed better than concrete slabs. The better performance of houses on piled foundations may also be a consequence of the timber ground floor which can accommodate differential settlement of the foundation system more easily than a concrete slab."
"A small number of buildings on poor soil sites have driven timber or concrete piles under the concrete slab, but it is not possible to identify these buildings from a visual inspection. There are several verbal accounts of buildings with driven piles performing much better than neighbouring buildings with simple concrete slabs."
Very interesting reading. Maybe this will promote a rethink or revise of some of the building codes? That can only be a good thing?
Another quote " Concrete slabs and pile foundations were observed to perform very differently on liquefied sites. This was clearly illustrated at an Avondale residence consisting of an older (1950"s) house, partly built on concrete pile foundations and newer (1997) extensions built on a concrete slab. The older part of the house on piles remained relatively plumb compared to the newer part. The large settlements of the slab foundations caused extensive structural damage at the interface between the old and the new structure. Similar observations were made on sites where a garage or carport on a concrete slab was connected to a house on pile foundations, giving differential movement between the two foundation types resulting in damage to the wall and roof structure of the building. In general, for areas where there has been soil liquefaction, pile foundations performed better than concrete slabs. The better performance of houses on piled foundations may also be a consequence of the timber ground floor which can accommodate differential settlement of the foundation system more easily than a concrete slab."
"A small number of buildings on poor soil sites have driven timber or concrete piles under the concrete slab, but it is not possible to identify these buildings from a visual inspection. There are several verbal accounts of buildings with driven piles performing much better than neighbouring buildings with simple concrete slabs."
Very interesting reading. Maybe this will promote a rethink or revise of some of the building codes? That can only be a good thing?
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