The building crack shown in the figure is a _______ crack. 

Explanation:

Diagonal Cracks:

• The crack follows a stair-step pattern, moving diagonally across the wall through the mortar joints, which is typical in brick masonry walls.

• Diagonal cracks like these are usually caused by foundation settlement, differential movement, or lateral loads such as seismic activity or soil pressure.

• These types of cracks are often signs of structural distress and should be carefully investigated to assess the extent of damage and required repair.

Additional Information

Here is some additional information related to diagonal cracks in brick masonry walls:

Causes:

1. Foundation Settlement: Uneven or differential settlement causes stress in the wall, leading to diagonal cracks.

2. Soil Movement: Expansive soils (like clay) swelling or shrinking due to moisture changes can shift the foundation.

3. Seismic Activity: Earthquakes can impose lateral forces that lead to diagonal shear cracks.

4. Lateral Loads: Wind or earth pressure on retaining walls may cause such cracks.

5. Poor Construction Practices: Lack of proper bonding, inadequate curing, or weak mortar may contribute.

Effects:

• Can lead to water seepage and reduced structural strength.

• May indicate serious underlying problems in foundation or soil.

Remedial Measures:

• Foundation strengthening (e.g., under-reamed piles, jacketing).

• Grouting or epoxy injection to seal cracks.

• Stitching technique using steel rods across the crack.

• Replacing or strengthening the affected masonry units.

Monitoring crack width and propagation over time is also a good practice to assess the severity.