A few questions on an old brick masonry project 2

[hemiv]

Hi all.

I'm working on a small residential renovation project. This is a late 19th c. brick building. The project is on the interior of the building, and a lot of the walls are covered with gypsum board or painted. I've worked on similar buildings, but none with this much involvement with the brick itself. A few questions:

[ul]
[li]Should I be requiring ASTM C1314 prism testing? There are a few pockets to be made for new beams, and this brick could be used to make test prisms. I'm keeping the new bearing stresses below 100psi.[/li]
[li]If not, I would like to check the masonry with some non-destructive testing. Do you do this? What kind of equipment is accessible? I'm aware of rebound hammers, but I've never personally used them to approximate strength, and am more familiar with them being used on concrete.[/li]
[li]Similar question for the mortar. I am requiring testing to confirm the cement to lime ratio in order to specify the new mortar, but should anything else be done?[/li]
[/ul]

 

[dik]

For some information, catch the file... (file updated)

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1700200652/tips/Historic_Brickwork_23-11-16_aqwlt2.pdf[/url]

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[milkshakelake]

Non-destructive testing like Windsor probe has the issue that it will test differently at the brick and mortar. Prism test is more holistic and will test brick and mortar together.

ASCE 41-17 Seismic Evaluation and Retrofit of Existing Buildings Table 11-2a has some lower bound strengths you can use for unreinforced masonry. I'd check the limitations and see if it applies to your case.

 

[BAretired]

At a conservative bearing stress of 100 psi, I would skip the test and just do a visual.

 

[hardbutmild]

I agree with BA that 100 psi should be well below strength.

Personally, I had a bad experience with most tests on historic masonry and would recommend visual examination and compare it with what the code suggests.

I quite like the masonry quality index (MQI) proposed by the italians, it gives a lot of data based on visual inspection (apparently it was calibrated with a large number of tests).

https://www.researchgate.net/public...alysis_and_classification_of_historic_masonry