Bonding Joints Q2

Thomas Sim PEA2066

Q.
a) 'Brick bonding must be overlapping and continuous vertical joints should be avoided.' Explain and show how to overcome the problem. (13 marks)

b) By using diagrams, describe the types of bond suitable for the following uses:

i) Retaining walls
ii) Partitions
iii) Arches and lintels (12 marks)

(25 marks, 2013 Q2)

A.
a) Earlier post on Past year 2011 Q4 elements of a brick wall opening is referred.

[For a big piece of wall, expansion and constriction due to heat and cold requires the allowance of space (thus, opening) to avoid cracks. In such circumstances, brickwork may be specifically allowed for provision of 'weakness' thus, employing the continuous vertical joints concept - herein referred as vertical expansion joints. Below is an extract of a written article on such provision.]

The presence of openings in the wall changes the manner in which the movement takes place. Each wall section with a different horizontal length expands outward from its centerline. Thus, wall components are moving different distances and perhaps in opposite directions. That movement causes stress concentrations and cracks unless vertical expansion joints are positioned properly. Typically, the expansion joint locations are more frequent than 25’ oc in walls with frequent punched window openings.

 

The above question however, asked on the brickwork methods to avoid this weakness, thus avoiding the continuous vertical joints.

The various ways to lay the bricks are describe below.

In order to avoid continuous vertical joints, the various methods of overlapping brickworks are shown below.

Ref:
Brochelt, Gregg. Brick Expansion Joints and Wall Openings design element minimizes movement cracking. Article reprinted with permission from Vol 38 No 4 The StoryPole – AIA Celebrates 150
Years.
Various methods of brickwork, available at
http://www.ibstock.com/pdfs/get-it-right/getitright4.pdf

b)
i) Bonding used in retaining walls.

Retaining walls - English Bond, Flemish Bond.
Running or Stretcher bond: This is the simplest ofall bond patterns and also most commonly used pattern. This pattern consists ofall Stretcher bricks (full bricks) in courses. The Stretchers inalternate courses are aligned vertically. It’s easy to lay with little waste.
 
Running or Stretcher bond
Common or American bond or English garden wall bond: Thisbond is a variation of the running bond with a course of full-length headers atregular intervals, generally every fifth, sixth, or seventh course.
Common bond English bond: This pattern consists of alternatecourses of headers and stretchers. The headers are centred on the stretchers.And the joints between the stretchers in courses are aligned vertically. Thisbond is the strongest bond for one-brick-thick wall. But, it’s seldom used inmasonry today due to high cost of laying a complex pattern.
English bond
 
English cross bond: This pattern is similar to Englishbond. But it differs in that vertical joints between the stretchers inalternate courses do not align vertically. Sometimes, this bond pattern is also called Dutch bond. But, Dutch bond is little bit different. I’llshow it in another post.

 

English cross bond
Flemish bond: This is the beautiful bond. Each courseof bricks of this bond consists of alternate stretcher and header. The headersof each course centred over the stretchers of the course below.

 

 

Flemish bond
Ref:
http://acivilengineer.com/2011/11/traditional-brick-bond-patterns-used-in.html
ii) Bonding used in partitions.
Partitions - Common Bond

This is the most common bonding used for economy and convenience of carrying out the brickwork. In this arrangement of bonding, all the bricks are laid as stretchers. The overlap, which is usually of half brick, is obtained by commencing each alternate course with a half brick bat.

Stretching bond is used for half brick wall only. This bond is also termed as running bond and is commonly adopted in the construction of half brick thick leaves of cavity walls, partition walls, etc. Since there are no headers, suitable reinforcement should be used for structural bond.

Ref:
Types of brick bond. The construction civil, available at
http://www.theconstructioncivil.org/types-of-brick-bonds
iii) Bonding used in arches and lintels.

 

Arches and Lintels
Arches and Lintels need to accommodate shear forces and loads from sides and above. Arches depend for their success on abutments at each end capable of providing adequate support to resist the force generated by the arch. The shape and rise of the arch are important because some arches provide much better support than others.
Brick arches can be formed using standard shaped bricks with tapering masonry joints to get the curvature required. Specially made tapered bricks with constant thickness joints can be used. Standard shaped bricks can be cut to a wedge shape to form the arch, with constant thickness mortar joints. Purpose made special shaped bricks are also used.
A soft, orange colour, brick known as a "red rubber" is often used for high quality work. These bricks are rubbed with abrasive material to form the correct shape and are formed to fit tightly together with joints often no more than 1 or 2 mm wide. The joints are filled with lime putty giving the classic white appearance to the mortar. Occasionally yellow "rubbers" can be seen used in buildings.

Ref:
Chris Shaw. Arches and Lintels: Part 1 - Arches. A structural look at Arches and Lintels, available athttps://www.localsurveyorsdirect.co.uk/arches-and-lintels-part-1-arches