Masonry Internal Wall Design Flashcards
How is ultimate applied load, F (per metre length of wall), calculated?
Floor dead load + Floor live load + Roof dead load + Roof live Load + block self weights
How is the clear height of a wall panel calculated?
Height - thickness of floor (or roof)
How is effective height reduction factor calculated?
What value should it not exceed? If it does exceed this value, what do you do?
0.5 x (total height / clear height)
Should not exceed 0.75, if it does, take the value as 0.75
How is effective height (Hef) calculated?
Effective height factor x clear height
What needs to be calculated for cavity walls after the effective height?
Effective thickness (Tef)
After cavity effective thickness is calculated, what must be calculated?
Slenderness ratio (Hef / Tef)
What must the slenderness ratio (Hef / Tef) not exceed?
27
What must be calculated after the slenderness ratio?
Area reduction factor
What is the area reduction factor equal to?
If the area is greater than 0.1m2 it is 1.0, if it is less than this then it is (0.7 + 3A)
How is capacity reduction factor obtained?
Using one of the three equations from table M8
How is F/A calculated?
What units should it be in?
The ultimate force per metre length calculated first
Divided by
1m width x thickness
N/mm2
What should be calculated after F/A?
Masonry design strength required, Fd
Using the required design strength calculated, what must be calculated next?
What table must be used?
Masonry characteristic strength, using the required masonry strength multiplied by the partial safety factor in table M5
Where is mortar strength found and what mortar strength should be specified?
Table M1, start with M6 typically
What table is used to choose a suitable grade of block?
Table M4
How is the required masonry compressive strength calculated?
Using the mortar value you specified and the Fk value (masonry characteristic strength), use interpolation to find Fb
How do you check the interpolated values?
Using equations in table M3
How is the actual compressive strength calculated?
Fb / shape factor (from table M2)
How is the shape factor obtained?
Using the dimensions of the block specified in the question, the shape factor is obtained from table M2
What is the formula for interpolation?
Y = Y1 + (X - X1) x ((Y2 - Y1) / (X2 - X1))
How do you check for wind loading?
- Divide the total ultimate design load per metre by the partial factor for safety of live loads (Ned)
- Calculate load ratio (alpha)
- Use interpolation of table M6
- Calculate min thickness (t) and then check wall thickness exceeds this
What Eurocode is used for masonry?
EC5
During the calculation for effective thickness, what is…
t1?
t2?
t1= thickness of brickwork outer skin
t2= thickness of blockwork inner skin
When using external walls, what must you multiply the load by in calculations?
2
When using internal walls, what must you multiply by in the load calculations?
4
In internal wall calculations, what is Tef equal to?
The thickness of the blockwork (if single skin)
For external walls restrained at the top and bottom, what should the effective height factor not exceed?
For internal walls where the wall is not the end wall and has rotational restraint, what should the effective height factor not exceed?
External - 1.0
Internal - 0.75
