Test need to carry on clay bricks of existing structure 2

[gosai]

I have a restoration project of old brick building, in order to evaluate existing condition of the structure we took out some brick samples from the structure. I recommended to test for compressive strength of bricks. is there any other tests required to carry on brick sample to know durability and other Characteristics of the brick?

Thanks everyone in advance

 

[Ron]

Check absorption and friability. Cut a cross-section of the brick and determine its relative hardness through the cross section. Old brick were noted for having incomplete firing, thus creating a hard outer shell, but having low strength, unfired clay in the middle.

Attached is a photo of a cross section of brick, circa 1900, that had typical low strength, friable structure, inclusions, and cracks within the brick.

 

[dcarr82775]

It is very useful to get a couple of in place shear strength tests. Helps a lot since lateral loads tend to be tricky in older URM buildings.

 

[concretemasonry]

Compressive strength testing is not really important because the standards are to low or high and frequently are not really important.

I suggest you target on the problems and concerns you have and then spend the time and money on the appropriate tests that may be factors in acceptibility.

As an example, many 4 story buildings have been built to preform under either U.S. or BS standards using partially fired clay brick (really bad brick) because of the loads and conditions.

In the U.S. you could have a problem with very well fired, very strong (compressive strength)old clay brick, since other properties are important for different structures.

Keep in mind the with masonry design and analysis the wall is a structural element, just like a poured in place panel that may have proper placement and/or curing. The individual unit compressive strength MAY be important, but too high mortar strengths could be a bigger problem (per ASTM C270 - Appendix 1).

The brick properties are just one of the easiest things to look for, but other factors are more important, so try to narrow down the important factors and just not the easiest to test for.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.