Braces for concrete support safety question

In summary: The people on thaivisa forum are concerned that the braces installed after the mall was built may contribute to the instability of the mall.I contacted the Civil Engineering Department at my local university. They said that I should not be looking to them for advice on the internet, and that I should contact the Mechanical or Civil Engineering Departments at my local university (or the one that's closest to me).If this is a newer structure, unbraced and unsupported columns MAY (and I stress this, MAY) be subject to punch through, especially if there are large distributed loads on the floor(s) above, and insufficient columns (or insufficient girth of columns). If this is an older structure
  • #1

morrobay

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These braces were installed on the concrete support pillers at ground level of a very large 6
level mall.
Would the engineers comment on the safety of this construction, in particular drilling through the concrete support structure
 
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  • #2
The above braces were installed after the original construction of a very large mall.
50 views and no evaluation from a mechanical or civil engineer ?
 
  • #3
69 views, and I'm not a civil engineer.

What is the effect of drilling holds, and inserting lags with plates into a tunnel wall? It strengthens the brittle wall material from shear forces. The lags in the concrete column together with the steal plates have about the same effect, I should guess.

How long are the lag bolts? We don't know. In any case this places the concrete surface elements under the braces under additional shear upon vertical loading. We still don't know why the plates were added in the first place.
 
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  • #4
This subject came up on thaivisa, a discussion forum in Thailand, in the Pattaya section.
The pillars are under a very massive newly constructed 6 level + mall in this seaside town.
Some members on the above forum recently felt tremers and shaking while inside the new mall. Another member observed and took photos of these after construction braces.
There is no communication between the members on the forum and the Thai construction company that did the work.
The concern by the forum members is the danger of the mall collapsing.
Since this could be very serious I am trying to research it as fast as possibe.
 
  • #5
morrobay said:
This subject came up on thaivisa, a discussion forum in Thailand, in the Pattaya section.
The pillars are under a very massive newly constructed 6 level + mall in this seaside town.
Some members on the above forum recently felt tremers and shaking while inside the new mall. Another member observed and took photos of these after construction braces.
There is no communication between the members on the forum and the Thai construction company that did the work.
The concern by the forum members is the danger of the mall collapsing.
Since this could be very serious I am trying to research it as fast as possibe.

You should contact the Civil (or Mechanical) Engineering Departments of your local university (or the one that's closest to you), and not be looking for advice on the internet (especially if you don't have a background in structural engineering). For the record, I am also not a civil (and especially, structural) engineer.

If this is a newer structure, unbraced and unsupported columns MAY (and I stress this, MAY) be subject to punch through, especially if there are large distributed loads on the floor(s) above, and insufficient columns (or insufficient girth of columns). If this is an older structure, and it hasn't yet punched through, then it's probably okay. If those bolts don't go all the way through (e.g. they're drilled in part way and then epoxied in place) it just puts the concrete (at the top of the pillar) in tension. Unless there is sufficient rebar (or similar support) concrete usually works in compression, and not tension.

If the denizens of the building actually are feeling quakes and shaking, this could be a sign that something is wrong. Or it could just be that the building is settling. However, the people at Sampoong also felt quakes and shaking inside their building shortly before collapse:
http://en.wikipedia.org/wiki/Sampoong_Department_Store_collapse

(There, the owner / architect got engineers to do preliminary work, got it approved, fired the engineers, and then started redesigning things and building bigger while removing supports). So contact a civil engineering academic, and do it ASAP! If they're the ones that do the analysis and figure out that this is a disaster in the waiting, it's both serving the public good (usually part of the academic / engineering mission) and good publicity.
 
  • #6
I think you've nailed it, MATLABdude.

This begins to sound very much like retrofitting in response to the building breaking up. As they are strengthening the floor-column connections, it's likely this is where cracks have been found on other columns. By the way, concrete columns are normally constructed around a rebar cage, so it should be the concrete-rebar composite that would be in tension from the extra hardware.

An additional avenue may be to push for legal injunction to condemn the building (but I aint a lawyer, either :smile: )

Is this a new construction or has the interior been changed? Has additional load been added recently, such as water storage or larger airconditioning units on the roof? Have any upper-story columns been removed to increase open space?
 
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  • #7
Thanks for the information and well taken advice.
This is a very new construction. Regarding recent additional loading;
Yes, there is a large crane on the roof and some sort of 2-3 story high unfinished construction ongoing above the completed 6 level.
 

What are braces for concrete support used for?

Braces for concrete support are used to provide additional support and stability to concrete structures during construction. They help prevent collapse or shifting of the structure while it is still being built.

What types of braces are commonly used for concrete support?

The three most commonly used types of braces for concrete support are diagonal, cross, and knee braces. Diagonal braces are used to prevent horizontal movement, cross braces prevent lateral movement, and knee braces are used to support walls or columns.

How do braces for concrete support enhance safety?

Braces for concrete support help distribute the weight and forces of the concrete evenly, reducing the risk of structural failure. They also provide temporary support during construction, preventing accidents and injuries to workers.

Do braces for concrete support need to be removed after construction?

It is recommended to leave braces in place for at least 7 days after pouring concrete, or until the concrete has reached its full strength. However, the exact time frame will depend on the type of braces used and the size and complexity of the structure. It is important to follow the instructions of a structural engineer for proper removal.

Can braces for concrete support be reused?

Yes, braces for concrete support can be reused for multiple construction projects as long as they are in good condition and meet the necessary safety standards. However, it is important to inspect them before each use and replace any damaged or worn out braces.

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