Existing structural material tests

[youngstructural]

Hello All;

We have an existing structure that we are renovating (removing interior load bearing walls and adding a second floor). We're going to specify core tests of existing concrete and tention tests on existing reinforcement, but I'm looking for a publication that will give guidance on who many cores and how many steel samples should be tested to arrive at reliable numberes for design.

The structure is reinforced concrete with a stone veneer, concrete flat slab construction on numerous internal load bearing walls. It was built in the 1930s and we do have complete construction drawings, but not the specification.

Does anyone know of an appropriate publication? And in either case your experience and advice would be greatly appreciated.

Cheers,

YS

B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...

 

[kilroy73]

The Missouri DOT has some info in their rating manual found here on page 7 -

http://modot.org/pdf/business/bridgesection_4.pdf

It's just a statistical analysis using standard deviations. The more samples you get the less uncertainty you apply to your "average" value.

I was in the same boat as you on a bridge - built 1931, plans but no specs, though a hint that "high early strength concrete" was used. I applied this method to concrete cores and windsor probe tests on the bridge (you may want to look into using windsor probes in lieu of cores). Individual tests showed strength as high as 9 ksi, only a couple lower than 7 but with around 12 samples, I ended up using 7 ksi for analysis. Pretty good for 1931 construction.

 

[youngstructural]

Thanks Kilroy; I've never seen the Missouri document, however I am very familiar with a the Canadian equivalent (PWGSC Bridge Inspection Manual). I'm looking for a guide on the application of detructive testing to buildings.

I will definately have a good look at the Missouri text though, thanks!

Cheers,

YS

B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...