Quetta Bond/Rat Trap Bond: brick buildings-Help please

[MaureenE]

Could anyone with knowledge of construction/bricklaying  tell me if the following paragraph I have written is accurate. Some of the information I found was a bit conflicting.

Quetta Bond

Quetta Bond is a technique developed after the Quetta earthquake, used in brick and other masonry buildings, where vertical reinforcement is used to improve horizontal and vertical bond between walls (see image)^[2]. It incorporates the bricklaying technique Rat Trap Bond (see image)^[3]

1.  
2. Jump up ↑ "Earthquake Risk Profile Risk Reduction & Technical Capacity in the EAS Member Countries" by Sudhir K Jain. nidm.gov.in. Scroll down
3. Jump up ↑ "Rat Trap Bond – A masonry technique" sepindia.org

 

Cheers

Maureen

[KevinBattle]

There have been several topics on the 1933 Quetta earthquake after which it was found that of the buildings that survived many had the "rat trap" bond in which alternate bricks are laid endwise across the inner and outer walls. I'm sure Wiki will have descriptions and illustrations.

Obviously, it was a bricklaying technique PRE Quetta, but because of its durability to earthquake shock the "Quetta bond" was used as a better name than "rat trap bond"!

[MaureenE]

Thank you  for your comments KevinBattle. My Googling hasn't been very productive. I can't find much on Quetta bond, apart from the reference in my original post, which indicates that it has reinforcement in it.  Do you have any links for the topics you referred to, which indicate that the buildings which survived the   Quetta earthquake used rat trap bond, as I haven't been able to  find any references to this.

 

Cheers

Maureen

[KevinBattle]

P18 has a diagram as to how the bricks are laid.  www.afps-seisme.org/content/download/1697/8132/file/Jain.pdf

P174 again has illustrations: http://www.iitgn.ac.in/seismic-design/files/An Overview of Earthquake Engineering (DCR).pdf

(Little trick is use the CTRL key and capital "F" together, which allows you to "Find" specific words in a text - there'll be a dialogue box on the top of the document for you to enter the Search term).

 

I was researching an RAF officer's WW2 experiences and he had been at the RAF Station nearest Quetts in 1935 (my mistake to put 1933 off the top of my head without checking). Reference to rat trap bond having superior EQ resistance made me look it up, as curious as to what it was.

 

Hope that helps!

 

 

[Guest]

The Quetta Bond is simply a slight variant of 1½ Flemish Bond where the voids are filled with concrete and steel reinforcement bars rather than brick..

 

It was almost certainly invented (if that is the right word) by Royal Engineers. The RE was heavily involved in the aftermath of the Quetta earthquake. From what I can tell (assuming the modern images are correct) the Quetta Bond is simply an 'opus insertum' variant of Flemish Bond (a common type of brickwork familiar to most British bricklayers along with English Bond and Garden Bond). In Flemish Bond the bricks laid with alternate lengthways (stretchers) and head on (headers); each stretcher has another one behind it, so the 'wall' is usually one brick length wide. Flemish bond is one of the most common techniques. It was first used on the English east coast as the Dutch trading ships used to use surplus bricks (slightly smaller than English bricks) as ballast in their boats. The east coast of the UK has lots of vernacular architecture with Dutch influences. 

 

There are variants of Flemish Bond which can be traced back hundreds of years. One is a "1½ Flemish Bond" which has cavities and was used hundreds of years before the Quetta Earthquake. 1½ Flemish Bond simply adds a brick width by stepping the 'inner' course back by the width of a single brick and shifting it laterally half a brick to cover the back of the header. This creates a cavity ('opus') which was usually filled with half bricks. If left open, it could be filled with other material such as rubble or concrete. Quetta Bond simply uses concrete and  - critically - reinforcing bars. The technique of building walls with cavities that were filled with concrete is known as opus insertum and was know to the Romans, so not exactly revolutionary. The RE were rather adept at improvisation and plagiarism.

 

Rat-trap bond is quite different (and I think misleading as a comparison in this sense) as its bricks are laid on their thin edge (albeit following 1½ Felmish Bond). It was a way of making the bricks go a lot further (height). It's unique feature was the thin edge laying, not just the openings. The openings were common to 1½ Flemish Bond and Rat Trap Bond.

 

The RE Museum might be able to guide you to some original material. I would be amazed if the RE Journal of the 1930s didn't have an article on it. 

 

Any mistakes are mine

 

MG  

 

(two lifetimes ago a graduate in Architecture: (BA (Hons) for my sins)...and more importantly an ex Queen's Gurkha Engineer 'where we did our work on water'..)

Edited 12 September , 2016 by Guest

[MaureenE]

Many thanks to you both for the information.

Cheers

Maureen