What Causes Defects?

Structural movements from inadequate design, faulty construction or overloading.
Ground movement.
Defective materials.
Chemical action (e.g. timber decay, sulphate attack)
Moisture & thermal movements (e.g. clay expansion)
Defects arising from conditions above ground.

What to Check on a Leaning/Bulging Wall

Check for loss of support to other elements.
Check position & bonding of lateral restraints.
Check if floors, roof & upper walls are contributing or restraining lateral movement.
Check if it's a cavity or solid wall.

Remedial Measures for Leaning/Bulging Walls

Tie rods through floor or roof level to tie opposite walls together.
Tie back floor joists and roof members to provide restraint and reduce SR (slenderness ratio).
Key buttresses into a wall & carry them down to a stable base (requires adequate space)

What Influences the Type of Measure Required for Crack Repairs?

What are the Remedial Measures for Cracks?

Remedial Measures for the Failure of a Junction Between Structural Walls

What are the Remedial Measures for the Failure of Built-in Timbers?

What are the Remedial Measures for the Corrosion of Ferrous Metals?

Remove corroded metal & fill cavity.
If unable to remove, remove surrounding brickwork, clean metal & treat with rust inhibitor & try reduce moisture penetration.

What are the Remedial Measures for Corroded Wall Ties?

What is Sulphate Attack?

The chemical breakdown of cement.
Signs: expanding/whitening of mortar joints, horizontal cracking, friable joints & increased height/length of wall.
Remedial Measures: demolish & rebuild affected areas OR remove/protect from source of dampness.

What are the Remedial Measures for Thermal & Moisture Movements?

Establish cause of cracking.
Insert movement joints at suitable positions.
Use dry/mature bricks with sufficient movement joints to prevent damage in new buildings.

What is Efflorescence?

Commonly occurs on surface of new bricks as they first dry out.
Brushes off & normally disappears after two springs, if not, indicative or abnormal water penetration.
Remedial Measures: check for defective dpc or rainwater goods & cut out and replace badly deteriorated bricks.

What is Frost Action?

The formation of ice crystals within components already saturated with water during cold weather.
Signs: spalling faces of bricks & disintegration of mortar.

	Erstellt von d.moran-10 vor mehr als 10 Jahre

Undergraduate MIS & MRR (Summary of MRR Revision Topics) Notiz am Masonry Defects - Summary, erstellt von d.moran-10 am 19/05/2014.