building brick walls on "propped" structure ? Now it cracks after de-propping

[lolobau]

Hi, I have some problem because the contractor was building brick walls on propped structure.
Now what happens after they "de-propped" the slabs, the bricks started to crack here and there.
How can I prove to the contractor that this was wrong? Obviously he is now arguing that why was he not supposed to build the brick walls on propped structure.
Where can I get some written proof that this is not allowed? Do the building regulates and codes mention it?

 

[cvg]

well the designer could estimate it during design, but actual is likely to be different. he doesn't know much or anything about the actual propping, the actual strength characteristics of the slab. is the propping pushing the slab up, or is it sagging a little bit before or after removal? how many days since the concrete was poured? What mix was actually delivered to the site and what was the actual strength? Have environmental conditions or admixtures or something else delayed or accelerated the curing?

yes, a note should be on the plans and that will at least protect the engineer. But don't count on a contractor reading it

 

[rapt]

That would require a quaint old fashioned practice which used to be part of the engineers brief, often called inspection or supervision. And important requirements were often discussed at the beginning of a project to set the ground rules.

 

[dik]

Rapt and CVG:

"" Of course the engineer could not know ahead of time how much it would deflect after removing the props"

Why wouldn't the designer know. It is part of the design calculations, if the designer wants to put in the effort to do them properly."

and, of course, you would expect the contractor to know this?

Dik

 

[cvg]

of course this "quaint old practice" is not always practiced. it is not the engineers job to supervise a contractor. contractually it is usually not allowed. and full time inspection is only done on some projects. maybe things are different in other countries.

apparently neither was done on lolobau's project.

 

[rapt]

CVG,
"quaint old practice"

Probably not in other countries either, more in past times, before the age of project managers, where designers had more control and were actually paid to do their job properly, until the construction was completed. I should have added a smiley (or sad) face!

dik,
I have never made the assumption that a builder actually understands engineering or design. Some understood if explained properly, others simply have no idea what you are talking about. And getting them to read notes on a drawing!! And that is where the problem with lack on involvement of the building designers in the construction process and supervision/inspections rears its ugly head.

 

[dik]

rapt: Yup...

Dik

 

[BLSPAM]

If the brick is repaired will the problem persist? If the support structure was adequately designed then the contractor may have made a mistake. Things get very confusing in a courtroom and nobody comes out ahead. The team should address a solution and, unfortunately, the cost should be shared by all, including the owner.

 

[BAretired]

What did the owner do wrong?

BA

 

[jike]

What was the deflection and span of the beam supporting the masonry wall? Assuming the slab is poured before the wall was built, the deflection that the wall will potentially see is the weight of the wall plus the floor live load.

 

[Ingenuity]

...the deflection that the wall will potentially see is the weight of the wall plus the floor live load.

And don't forget that 'pesky' creep and shrinkage deflection that will occur over the lifetime of the slab.

 

[dik]

BART... he was the one benefiting from the 'reduced cost'...

Dik

 

[BAretired]

dik...I should have known...

BA

 

[rapt]

jike,

You missed the bit about the slab still being propped when the wall was built. So the wall experiences the full deflection including the slab Sw and the wall weight as well as loads added afterwards and the resulting cracking effects. And the long term effects as mentioned by Ingenuity.

 

[jike]

rapt,

Yes, I missed that. So, what is the total deflection?

 

[lolobau]

Hi guys, I am quite surprised about all the comments. Thanks for all the infos. Let me uplaod an image which will explain what was happening.

 

[lolobau]

and this is what is happenign after removing of the propps

 

[lolobau]

I just can't fine any any article on the net which would deal with this topic "building a masonry wall on a shored floor"

 

[LittleInch]

Bottom line here to the original question - "why was he not supposed to build the brick walls on propped structure" is that the prop was a temporary construction feature - presumably included by the contractor - to assist with construction of the base slab. It was not part of the permanent design and therefore needs to be removed prior to building anything else on it.

So unless you told him to build the brickwork with the props still in place, the responsibility and schedule for any temporary construction works remains with the contractor. End of.

I'm a little surprised something that size moved enough to cause significant issues, but you have the evidence in front of you.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[dik]

Is the cracking at the mortar joints, or, through the masonry units... almost worst place for a door opening with the large cantilever on the left... Judging from the sketch, it appears cracking through the masonry units.

Dik

 

[lolobau]

@littleinch: thanks for support, you make feel better ;-)
I like your statement " "why was he not supposed to build the brick walls on propped structure" is that the prop was a temporary construction feature" this covers me a bit

I attached a photo of the site