Masonry cracking
Masonry cracking
(OP)
I have a client who asked me to look at an existing building that has developed some cracks. The customer is concerned that the cracks pose a structural risk to the building.
The building was constructed 11 years ago. The building is 100’ wide x 200’ long x 26’ tall steel framed with 8” masonry walls used as infill. I visited the site over the weekend and took a few pictures. The building is oriented in such a way that the 200’ side faces the east and west direction. Some of the cracks (which have already been repaired) occur on the each 200’ long side but not the 100’ long sides.
A few things I noticed:
-Masonry contraction joints are at 40’ o.c..
-no visible contraction joints were observed in the foundation wall (only construction joints).
-Masonry joints do not align with construction joints.
-Cracks are concentrated at the bottom 3-4 courses of masonry and are above foundation cracks.
-The building is constructed in an area that tends to have a lot of sand (I don’t know this for certain).
The cracks almost look like shrinkage cracks…..but the building has been in place for 11 years so unless the cracks are just opening up now…. Or nobody ever saw them before, I don’t know.
Does anyone have any idea on what the cracks might be cause by?
The building was constructed 11 years ago. The building is 100’ wide x 200’ long x 26’ tall steel framed with 8” masonry walls used as infill. I visited the site over the weekend and took a few pictures. The building is oriented in such a way that the 200’ side faces the east and west direction. Some of the cracks (which have already been repaired) occur on the each 200’ long side but not the 100’ long sides.
A few things I noticed:
-Masonry contraction joints are at 40’ o.c..
-no visible contraction joints were observed in the foundation wall (only construction joints).
-Masonry joints do not align with construction joints.
-Cracks are concentrated at the bottom 3-4 courses of masonry and are above foundation cracks.
-The building is constructed in an area that tends to have a lot of sand (I don’t know this for certain).
The cracks almost look like shrinkage cracks…..but the building has been in place for 11 years so unless the cracks are just opening up now…. Or nobody ever saw them before, I don’t know.
Does anyone have any idea on what the cracks might be cause by?






RE: Masonry cracking
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Masonry cracking
The building is in the North East which had tons of snowfall (which would insulate the foundation against thermal fluctuations). The building has also been occupied since it was built by the same owner and is very well taken care of. As I visited on the weekend I was not able to go inside. Also, on the west side, the foundation is only exposed for 6-8" on the east side the grade changes a little more allowing for exposure of the foundation (you can see some parging on the foundation wall in the pictures I attached).
I was thinking possible thermal movements of the masonry in relation to the foundation.
RE: Masonry cracking
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Masonry cracking
RE: Masonry cracking
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Masonry cracking
RE: Masonry cracking
They are not structural. - Probably due to a lack of enough joint reinforcement or no intermediate bond beam for a 26' high wall.The original cracks probably occurred in the first year or so after construction. For the 100' long walls, they may not be not be 40' long panels
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Masonry cracking
The repairs you can see in the photos are new (less than a year old). From what I have been told, there is a horizontal bond beam at elevations 13' and 26'. I have yet to see the drawings so I don't know if there was any joint reinforcing or what the spacing was. The description of the structure would lead you to believe that there is horizontal joint reinforcing at a minimum of 16"o.c. Typical reinforcing for the area is #9 ladur reinforcing at 16"o.c. (every other course).
I found other cracks that were not repaired, maybe they were too small as I had a hard time seeing them. Took me 10 min to figure out what they client was talking after visiting the site. So the cracks are small.
So is it masonry shrinkage, concrete foundation shrinkage or a combination of the two?
RE: Masonry cracking
RE: Masonry cracking