Masonry walls and introduction

Introduction

  • Brick bonds are an essential part of wall structure.
  • Brick is a standard-sized weight-bearing building unit.
  • Several bricks are laid together in stacks.
  • A structure made up of individual blocks of materials such as stone, brick, concrete, hollow blocks, cellular concrete.
  • Mortar paste is placed on top of each to form a firm bond.
  • Usually placed in horizontal courses/direction.
  • Cemented together with some form of mortar.

What is Brick Masonry

  • Brick: Brick is a building unit, which is in the form of rectangular block in which length to breadth ratio is 2 but height can be different.
  • Masonry: Construction of building unit bonded together with mortar.
  • Brick Masonry: The art of laying bricks in mortar in a proper systematic manner gives homogeneous mass which can withstand forces without disintegration, called brick masonry.

Brick  Masonry Uniqueness

  • Fire resistance
  • Size durability
  • Workability
  • Economical

Bonds in Brick Work

  1. English bond
  2. Flemish bond
  3. Header bond
  4. Stretcher bond
  5. Facing bond
  6. English cross bond
  7. Brick on edge bond
  8. Dutch bond
  9. Raking bond
  10. Garden wall bond

Types of masonry

  1. Stone Masonry
  2. Brick Masonry
  3. Hollow block concrete masonry
  4. Reinforced Masonry
  5. Composite Masonry

Failure of Masonry

  • There are three ways in which a masonry building wall may collapse…
  1. The wall may fall straight out in a monolithic piece at a 90 degree angle.
  2. The wall may crumble straight down in a so-called curtain fall collapse
  3. The wall may collapse in an inward/outward fashion

90 degree failure

  • This is the most common type of masonry wall failure which occurs at fires. The wall falls straight out and the top of the collapsing wall strikes the ground, a distance equal to the height of the failing section measured from the base of the wall. A fifty foot section of wall collapsing in a 90 degree angle fall will cover at least fifty feet of ground with brick. Bricks and steel linters may bounce or roll out even farther.
  • The wall begins to lean outward at the top, separating from the other enclosing walls, and falls straight out at a 90-degree angle.
  • Occurs at fires.
  • The wall falls straight out and the top of the collapsing wall strikes the ground, a distance equal to the height of the failing section measured from the base of the wall.

Curtain fall collapse

  • In this type of collapse, the exterior masonry wall drops like a falling curtain cut loose at the top. The wall crumbles and falls straight down, with bricks and mortar forming a pile on the ground near the base of the wall. The collapse of the brick veneer, brick cavity, or masonry-backed stonewall often occurs in a curtain-fall manner.
  • The exterior masonry wall drops like a falling curtain cut loose at the top.
  • The wall crumble and falls straight down, with bricks and mortar forming a pile on the ground near the base of the wall.
  • The collapse of the brick veneer, brick cavity, or masonry-backed stonewall often occurs in a curtain-fall manner.

Inward/Outward collapse

  • When a masonry wall becomes unstable and begins to lean inward, it does not always mean that the wall will fall inward. Firefighters operating ground streams must still maintain a safe distance between themselves and the unstable walls, for when a section of the broken wall falls inward, the lower portion of the wall may kick outward, of the upper portion may initially fall inward but then slide down and outward into the street, bottom first, known as an inward/outward collapse.
  • When a section of the broken wall falls inward, the lower portion of the wall may kick outward, or the upper portion may initially fall inward but then slide down and outward into the street, bottom first.
  • When a masonry wall becomes unstable and begins to lean inward, it does not always mean that the wall will fall inward.

Extras

  • By increasing the mortar joint thickness, the strength of the masonry will decrease.
  • The maximum compressive strength of models was obtained when the thickness of the mortar joint was 7.5mm.

Advantages of masonry wall

  • Increase the thermal mass of a building.
  • Provide a structure with reduce life-cycle costs.
  • Very heat resistant & thus provides good fire protection.
  • More resistant to projectiles.

Conclusion

  • Masonry boasts an impressive compressive strength but is much lower in tensile strength unless reinforced.
  • Brick masonry increases the thermal mass of a building and thereby resists fire.
  • Masonry tends to be heavy and must be built upon a strong foundation, such as reinforced concrete, to avoid settling and cracking.

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