QUOTE(zeroty @ Nov 12 2024, 12:17 PM)
Yes.
If it is foundation problem, building settled still can do underpinning.
This case is a severe structural failure at the bottom of the building. Unlikely to be fixable.
hm, let share something..
IF ya, IF only ya, if the scenario (let call Scenario 1), the settlement started at foundation, which founded on the incompetent limestone formation, and the foundation has caused the settlement and the basement structure settlement as more than 100mm as rumoured.
The structural wall at the lowest unit (above the carpark) cracked severely.
A finite element structural (FEM) model shall be conducted, to simulate the current situation which some wall supports have been damaged (or lost), with push over analysis, to theoretically identify affected structure (wall, structural framing elements, transfer structure), to check what is the extent of the stresses re-distribution. Of course, this is desktop study, asbuilt on site investigation also needed to be done to verify whether currently damage extent matching the analysis part (how much the building deformed, what kind of cracking behaviour, etc). To determine the structure (whole part) whether is in overstress condition above ultimate design resistance? or above service limit stage but still within the ultimate design requirement? for all the structural elements.
Ok, i try to simplify this, if a table lost 1 of it's leg (out of many legs, maybe 5 maybe 6 maybe more), and if the table is still stable, means the adjacent legs may act to help this OKU leg, and we need to understand the situation of remaining legs. And building structural framing is more complex than this.
This part is relatively straight forward if you got a good engineering expert to do.
Ok, come to slightly tedious part. Further to scenario 1, IF (if again ar) the building found to be in accepted deflected position (in layman, not titled very badly and acceptable structural tolerance), only part of the structural (maybe big part maybe small part) damaged and needed to be removed/strengthened/repaired, and only if the building is JACKABLE and PROPPABLE.
Next, you need to stabilise the building while removing damaged structural elements (or strengthen the building before any removal), this again, you need to reanalyse to check how much stresses are again re-distribute to the asbuilt structure. If you are jacking up the building, how much force and where to jack to reinstate the structure to it's original position or original design intended state. Wrong/Over/Inaccurate Jacking might cause others structure to experience more stresses, and further damage may occur.
Imagine, if you going to lift the lose leg table and replace 1 new. Yes, you easy can lift it up and install it, but in structural framing, all piles and structural framing is connected, you cannot lift it into air or overjacked (overpulled).
And the locked-in stress and design stress for each elements. Say, if the adjacent non-collapse wall (WALL A) was subjected to 10tonnes forces initially, but after the collapsed (lost of support) of other wall (small brother), say maybe WALL A subjected to 15tonnes forces now as it's small brother failed. Then if you going to build another new wall to replace OKU small brother, u also need to make sure this new brother takes back the 5tonnes from the WALL A, unless you can ensure WALL A can absorb this additional 5tonnes and still comply with the design compliances.
Also, IF for this scenario 1 failed by piles, means the asbuilt foundation and piles also needed to be reviewed and rechecked, another exercise needed.
Aiya, typed too long.... shud stop here....
No easy..... Hopefully our boleh land can get a right boleh expert to do so lah.
Haha, if other scenarios, then others story lah.
Nov 12 2024, 12:17 PM
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